This article provides a comprehensive framework for researchers, scientists, and drug development professionals addressing the complex challenges of wildlife parasitic zoonoses through a One Health lens.
This article provides a comprehensive framework for researchers, scientists, and drug development professionals addressing the complex challenges of wildlife parasitic zoonoses through a One Health lens. It explores the foundational interconnection between human, animal, and environmental health in parasite ecology, examines advanced methodological approaches for surveillance and intervention, troubleshoots critical implementation barriers from antimicrobial resistance to diagnostic limitations, and validates strategies through comparative analysis of successful case studies. The synthesis offers a transdisciplinary roadmap for developing innovative therapeutics and integrated control strategies that account for the ecological complexity of parasitic disease systems.
The One Health paradigm is an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals, and ecosystems [1]. It recognizes that the health of humans, domestic and wild animals, plants, and the wider environment are closely linked and interdependent [1]. This approach acknowledges that human populations are growing and expanding into new geographic areas, resulting in more people living in close contact with wild and domestic animals, both livestock and pets [2]. Furthermore, changes in climate and land use, such as deforestation and intensive farming practices, along with increased international movement of people, animals, and animal products, have created new opportunities for diseases to pass between animals and people [2]. The concept has evolved from the "One Medicine" approach suggested by Calvin Schwabe, a veterinary surgeon who highlighted the integrated, cross-disciplinary perspective that veterinary professionals could contribute to general medicine [3].
The One Health approach is particularly crucial for addressing zoonotic diseases, which are infections that are naturally transmitted between vertebrate animals and humans [4]. Currently, zoonoses account for 58% to 61% of all communicable diseases causing illness in humans globally and up to 75% of emerging human pathogens [4]. The approach encourages collaborative efforts of many experts working across human, animal, and environmental health to improve the health of people and animals, including pets, livestock, and wildlife [2]. This collaborative framework is essential for addressing the full spectrum of disease controlâfrom prevention to detection, preparedness, response, and managementâand contributes significantly to global health security [1].
One Health is defined as a collaborative, multisectoral, and transdisciplinary approach that operates at local, regional, national, and global levels, with the goal of achieving optimal health outcomes while recognizing the interconnection between people, animals, plants, and their shared environment [2]. This approach is not new but has gained importance in recent years due to changing interactions between humans, animals, and ecosystems [2]. The conceptual foundation of One Health rests on the understanding that a healthy human population requires a healthy ecosystem, which includes everything from the microorganisms living in our gut to our immediate environment and the world as a whole [3].
The One Health Quadripartiteâcomprising the World Health Organization (WHO), the World Organization for Animal Health (WOAH), the Food and Agriculture Organization of the United Nations (FAO), and the United Nations Environment Programme (UNEP)âhas identified six key focus areas for One Health implementation [3]:
These interconnected areas represent the strategic priorities for implementing the One Health approach globally and addressing complex health challenges at the human-animal-environment interface.
The operationalization of One Health relies on shared and effective governance, communication, collaboration, and coordination across multiple sectors and disciplines [1]. The approach can be applied at community, subnational, national, regional, and global levels, making it easier for people to better understand the co-benefits, risks, trade-offs, and opportunities to advance equitable and holistic solutions [1]. Successful public health interventions require the cooperation of human, animal, and environmental health partners, including professionals in human health (doctors, nurses, public health practitioners, epidemiologists), animal health (veterinarians, paraprofessionals, agricultural workers), environment (ecologists, wildlife experts), and other relevant disciplines [2].
The implementation of One Health platforms follows a structured approach to zoonotic disease surveillance and response. This includes establishing coordination mechanisms, case recording and disease detection systems, epidemic preparedness and response plans, mobilization of material resources, stakeholder training, and financing mechanisms [5]. Evaluation tools such as the Joint External Evaluation (JEE) and OH-EpiCap have been developed to assess and improve these systems, focusing on aspects such as resource availability, data collection and sharing, and data analysis and interpretation [5].
Figure 1: Operational workflow of a multisectoral One Health approach for zoonotic threat management
Evaluation of One Health platform performance utilizes standardized metrics to assess implementation effectiveness across different regions and contexts. The following table summarizes key performance indicators based on empirical studies:
Table 1: Performance indicators for One Health platform implementation
| Evaluation Domain | Performance Metrics | Assessment Method | Example Score (Guinea Study) |
|---|---|---|---|
| Coordination & Legislation | Existence of regulatory texts/manuals; Formal intersectoral consultation mechanisms | Document review; Stakeholder interviews | Legislation: 89% (Conakry region); Overall coordination: Limited |
| Epidemic Detection & Documentation | Presence of early warning mechanisms; Documentation of outbreaks | Surveillance system evaluation; Case reporting analysis | Significant heterogeneity across regions |
| Preparedness & Response | Existence of preparedness plans; Response mechanism activation | Plan review; Simulation exercises | Varied considerably between regions |
| Stakeholder Training | Availability of trained personnel; Training program implementation | Training records; Competency assessment | Limited trained personnel across sectors |
| Resource Mobilization | Availability of essential equipment; Funding allocation | Resource inventory; Budget analysis | Critically low: 9% across all regions |
| Funding Mechanisms | Dedicated budget lines; Financial sustainability | Budget documentation; Funding source analysis | Major cross-cutting challenge |
Data derived from a cross-sectional study conducted across eight administrative regions of Guinea revealed an overall One Health performance score of 41%, indicating limited implementation at the national scale [5]. None of the assessed regions reached the 60% performance threshold, with particularly low levels observed in Labé, Kindia, and Faranah (33%), underscoring major disparities in implementation [5]. The domain of material resources mobilization scored only 9%, highlighting a major cross-cutting challenge [5].
The prioritization of zoonotic diseases is essential for efficient resource allocation. Quantitative approaches like Conjoint Analysis (CA) have been employed to identify the relative importance of key characteristics of zoonotic diseases for prioritization in North America [4]. This method involves presenting participants with competing disease profiles containing both desirable and undesirable characteristics, forcing trade-offs that reveal the true value of each characteristic relative to others [4].
Table 2: Key criteria for zoonotic disease prioritization based on conjoint analysis
| Priority Criterion | Measurement Parameters | Relative Weight in Decision-Making | Application in Research |
|---|---|---|---|
| Transmission Potential | Basic reproduction number (Râ); Secondary attack rate; Spread velocity | High importance | Determines containment strategy and resource allocation |
| Severity & Mortality | Case fatality rate; Hospitalization rate; Disability-adjusted life years (DALYs) | High importance | Guides therapeutic development and emergency response planning |
| Economic Impact | Healthcare costs; Productivity losses; Trade/transport disruption | Moderate to high importance | Informs cost-benefit analysis of control measures |
| Surveillance Capability | Ease of detection; Diagnostic availability; Reporting completeness | Moderate importance | Identifies infrastructure gaps and laboratory needs |
| Preventive Capacity | Vaccine availability; Non-pharmaceutical intervention efficacy | Moderate importance | Directs vaccine development and public health measures |
| Vulnerable Populations | At-risk group identification; Equity implications | Variable importance | Targets protective interventions and risk communication |
A study involving 707 health professionals from Canada and 764 from the United States used Hierarchical Bayes models fitted to survey data to derive CA-weighted scores for these disease criteria, which were then applied to 62 zoonotic diseases to rank them in order of priority [4]. The results demonstrated that health professionals with knowledge in infectious diseases produced meaningful results with well-fitted models (83.7% and 84.2%), supporting the validity of this approach for zoonoses prioritization [4].
The investigation of wildlife parasitic zoonoses within a One Health framework requires standardized protocols that enable comparability across human, animal, and environmental samples. Laboratory investigations are a key element for the diagnosis of infectious diseases because their symptoms can often be non-specific, and full identification of the causal organism is important to determine treatment options [3]. The following experimental workflow outlines a comprehensive approach:
Figure 2: Integrated laboratory and analytical workflow for wildlife parasitic zoonoses research
Sample Collection Protocol:
Laboratory Diagnostic Methods:
The integration of data from multiple sources requires standardized data sharing protocols and analytical frameworks:
This integrated approach enables researchers to move beyond siloed investigations and develop comprehensive understanding of parasitic zoonoses dynamics within their ecological context.
The implementation of One Health research on wildlife parasitic zoonoses requires specialized reagents and materials that enable standardized, comparable investigations across species and sample types. The following table details key research solutions and their applications:
Table 3: Essential research reagents and methodological tools for One Health investigations of parasitic zoonoses
| Research Tool Category | Specific Examples | Application in One Health Research | Multi-Species Validation Requirement |
|---|---|---|---|
| Nucleic Acid Extraction Kits | DNeasy Blood & Tissue Kit; QIAamp DNA Mini Kit; Soil DNA extraction kits | Standardized DNA/RNA isolation from diverse sample matrices (human blood, animal tissue, environmental samples) | Required for human, domestic animal, wildlife, and environmental samples |
| PCR Master Mixes | Multiplex PCR kits for pathogen detection; Real-time PCR reagents with different fluorescent probes | Simultaneous detection of multiple parasites; quantification of pathogen load | Validation across human and animal samples to ensure equivalent sensitivity |
| Parasite-Specific Primers/Probes | Leishmania spp. kDNA primers; Toxoplasma gondii B1 gene primers; Echinococcus spp. primers | Species-specific identification and differentiation of parasites from clinical and environmental samples | Testing against related species to ensure specificity across wildlife hosts |
| Antigen Preparations | Recombinant proteins for ELISA (e.g., K39 for leishmaniasis); Crude lysate antigens | Serological detection of exposure; assessment of cross-reactivity between species | Standardization using reference sera from multiple host species |
| Cell Culture Media | Schneider's Insect Medium; RPMI-1640; Macrophage cell lines | Parasite isolation and cultivation; in vitro drug sensitivity testing | Adaptation for growth of zoonotic parasites from different host origins |
| Point-of-Care Tests | Rapid diagnostic tests (RDTs) for field use; Lateral flow assays | Field surveillance in remote areas; rapid screening of wildlife populations | Evaluation of performance characteristics in both human and animal samples |
| Environmental Sampling Equipment | Water filtration kits; Soil corers; Automated air samplers | Detection of environmental contamination with parasitic stages | Correlation with animal and human infection data |
These research tools form the foundation for integrated surveillance and investigation of parasitic zoonoses. The selection of appropriate reagents must consider their performance across the spectrum of sample types encountered in One Health research, from human clinical specimens to wildlife samples and environmental matrices [3]. Furthermore, the development of point-of-care tests suitable for use in field conditions is particularly important for surveillance in resource-limited settings where many parasitic zoonoses are endemic [3].
The One Health paradigm provides an essential framework for understanding and addressing the complex interconnections between human, animal, and ecosystem health, with particular relevance to wildlife parasitic zoonoses. The quantitative assessment of One Health performance across different regions reveals significant implementation challenges, particularly in resource mobilization and cross-sectoral coordination [5]. However, methodological advances in disease prioritization, such as conjoint analysis, offer promising approaches for rational resource allocation [4]. The integrated surveillance and laboratory methodologies outlined in this technical guide provide a roadmap for researchers investigating parasitic zoonoses within a One Health context. As the field continues to evolve, future efforts should focus on strengthening local capacities, harmonizing practices across sectors, and developing innovative reagents and tools that facilitate standardized investigations across the human-animal-environment interface.
Wildlife parasite ecology represents a critical frontier in understanding emerging infectious diseases and mitigating global health threats. This technical guide examines the complex interactions governing parasite transmission dynamics, the breadth of host spectra, and the environmental persistence of parasitic organisms. Framed within the One Health approach, which recognizes the inextricable interconnection between human, animal, and environmental health, this review synthesizes contemporary methodologies, quantitative data, and theoretical models essential for researchers and drug development professionals. The escalating incidence of zoonotic diseasesâfrom well-known threats like Lyme disease to emerging concerns like chronic wasting diseaseâunderscores the urgency of an integrated, cross-disciplinary strategy to study, monitor, and control wildlife parasites in an increasingly altered world [2] [6] [7].
The One Health approach is a collaborative, multisectoral, and transdisciplinary framework operating at local, regional, national, and global levels to achieve optimal health outcomes by recognizing the interconnection between people, animals, plants, and their shared environment [2]. This paradigm is particularly pertinent to wildlife parasite ecology, as the majority of emerging infectious diseases in humans are zoonotic, originating from animal reservoirs [8] [7]. Factors including human population expansion into new geographic areas, climate change, land-use alterations, and increased global movement of people, animals, and animal products have dramatically changed interactions between humans, animals, and ecosystems [2] [9]. These changes have facilitated the spread and emergence of zoonotic parasites, demanding a research approach that transcends traditional disciplinary silos. Effective public health interventions now require the cooperation of experts in human health (physicians, epidemiologists), animal health (veterinarians, agricultural workers), environmental health (ecologists, wildlife experts), and other relevant domains [2]. This guide details the core ecological principles of wildlife parasites through this essential, integrated lens.
Transmission dynamics describe the mechanisms and pathways through which parasites spread within and between host populations. Understanding these dynamics is fundamental to predicting and controlling outbreaks.
Parasite transmission occurs via several distinct routes, each with specific ecological implications:
Social network analysis has emerged as a powerful tool for quantifying heterogeneities in parasite transmission. Traditional epidemiological models often assumed random mixing among hosts, but network models capture the structured nature of animal behavior and sociality, which generates non-random contact patterns [10].
In a network model:
Table 1: Applications of Network Models to Different Parasite Transmission Modes
| Transmission Method | Parasite Example | Host System | Contact Type Defined in Network |
|---|---|---|---|
| Direct Contact | Trematode (Gyrodactylus turnbulli) | Guppy (Poecilia reticulata) | Physical contact [10] |
| Faecal-Oral | Nematodes (Oesophagostomum, Strongyloides) | Japanese macaques (Macaca fuscata) | Grooming interactions [10] |
| Environmental/Free-living | Tick (Amblyomma limbatum) | Sleepy lizard (Tiliqua rugosa) | Asynchronous use of common refuges [10] |
| Vector-Borne | Blood parasites (Hemolivia, Hepatozoon) | Egernia group skinks | Vector movement between hosts [10] |
The following diagram illustrates a generalized workflow for applying network analysis to study parasite transmission, from data collection to model interpretation:
The host spectrum of a parasite defines the range of species it can successfully infect. This spectrum can range from highly host-specific (infecting a single host species) to host-generalist (capable of infecting multiple species across different taxa).
The expansion of host ranges poses significant ecological and public health risks. When a parasite infects multiple species, it encounters diverse selective pressures and immune environments, which can promote genetic mutations and adaptive evolution, making it more difficult to control [6]. A prominent example is avian influenza (bird flu), which originated in wild birds but has since adapted to infect a broad range of birds and mammals, including dairy cows and humans [6]. This "mixing" of the virus in multiple species provides opportunities for recombination and mutation, increasing the risk of novel, highly pathogenic strains emerging.
Ecological Niche Models (ENMs) are computational tools used to predict the geographic distribution of a species based on environmental conditions at known occurrence localities. For parasites, the "ecological niche" exists at the intersection of abiotic and biotic conditions suitable for all its required hosts [11].
The Genetic Algorithm for Ruleset Production (GARP) is one model used to predict parasite distribution without complete knowledge of its life cycle. The process involves:
A study on the tapeworm Paranoplocephala macrocephala demonstrated that an ENM built for this single species could accurately predict the presence of 19 related parasite species across 23 different hosts throughout the Nearctic, suggesting shared ecological requirements among related parasites [11].
The survival and infectivity of parasitic stages in the off-host environment are critical determinants of transmission success. Environmental persistence is profoundly influenced by abiotic factors, many of which are being altered by global climate change.
Many parasites produce resilient environmental stages, such as spores, cysts, or eggs, capable of surviving for extended periods in soil, water, or vegetation. Prions, the misfolded proteins responsible for Chronic Wasting Disease (CWD), exhibit exceptional environmental persistence. They can remain infectious in soil for years, and the disease is "very contagious" among deer, elk, and moose, spreading both directly and through environmental contamination [6]. Similarly, the bacteria causing leptospirosis can persist in water and soil contaminated by the urine of infected animals, primarily rodents, with flooding events significantly increasing human exposure risk [6] [7].
Climate change acts as a major driver in the redistribution and increased incidence of wildlife and zoonotic parasites.
Table 2: Impact of Climate and Environmental Change on Select Zoonotic Parasites
| Parasite/Disease | Primary Vector/Reservoir | Documented or Projected Change |
|---|---|---|
| Lyme Disease | Deer Ticks (Ixodes scapularis) | Expanded geographic range northward and to higher elevations; increased infection rates linked to milder winters and higher host densities [6] [9]. |
| West Nile Virus | Culex mosquitoes | Models predict a five-fold increase in outbreak risk in the European region for 2040-2060 due to climatic suitability [7]. |
| Leptospirosis | Rodents, livestock | Rising temperatures and more frequent flooding amplify spread into human spaces, contaminating soil and water [6]. |
| Avian Influenza | Wild birds (ducks, geese) | Changing migratory patterns due to climate shifts facilitate global movement of the virus, enabling jumps to new species and regions [6]. |
Surveillance and historical data provide critical insights into the emergence, spread, and impact of major parasitic zoonoses. The following table synthesizes epidemiological attributes of several high-consequence diseases, highlighting their animal origins and transmission potential.
Table 3: Epidemiological Attributes of Major Emerging Zoonotic Diseases [8]
| Disease | Year of Emergence/ Outbreak | Causative Agent | Natural Reservoir | Intermediate Host(s) | Case Fatality Rate (CFR) |
|---|---|---|---|---|---|
| COVID-19 | 2019 | SARS-CoV-2 | Bats (potential) | Pangolin (potential) | Varies (e.g., <1 - 13.56%) |
| MERS | 2012 | MERS-CoV | Bats (?) | Dromedary camels | >35% |
| SARS | 2002 | SARS-CoV | Chinese horseshoe bats | Civets, raccoon dogs | ~0% (Note: Actual global CFR was ~11%) |
| Ebola Virus Disease | 1976 (recurrent) | Ebola virus | Fruit bats | Monkeys, apes, pigs | 25-90% |
| Nipah Virus Disease | 1998 (recurrent) | Nipah virus | Fruit bats (flying fox) | Pigs | 40-70% |
Robust scientific and surveillance methodologies are the backbone of wildlife parasite ecology, enabling researchers to detect, track, and understand emerging threats.
Table 4: Essential Research Reagents and Resources for Wildlife Parasitology
| Research Tool / Resource | Function / Application | Example Use Case |
|---|---|---|
| Global Mammal Parasite Database (GMPD) | A compiled database of parasites and pathogens from wild primate, carnivore, and ungulate hosts. Used to explore parasite taxonomy, transmission, prevalence, and global location [13]. | Baseline data for ecological and epidemiological studies on parasite biodiversity and host range. |
| Genetic Algorithm for Ruleset Production (GARP) | Software for creating Ecological Niche Models (ENMs) to predict species distribution based on environmental parameters [11]. | Predicting the potential geographic distribution of a parasite when its life cycle is not fully known. |
| Environmental DNA (eDNA) Sampling | Extraction and analysis of DNA from environmental samples (soil, water, feces) to detect parasite presence without directly observing hosts. | Monitoring water sources for Leptospira or soil in deer habitats for CWD prions. |
| ELISA/IgG Serological Assays | Detects host antibodies against a specific pathogen, indicating past or current infection. | Screening dog populations for exposure to Trypanosoma cruzi (Chagas disease) [12]. |
| Polymerase Chain Reaction (PCR) | Amplifies specific DNA sequences to detect and identify parasitic pathogens with high sensitivity. | Confirming active T. cruzi infection in a kissing bug or dog by detecting parasite DNA [12]. |
| Phorbol 12-tiglate | Phorbol 12-tiglate|High-Purity|For Research Use | Phorbol 12-tiglate is a phorbol ester for research use only. Explore its potential in studying Protein Kinase C (PKC) signaling and cell function. Strictly not for human or veterinary use. |
| Norrubrofusarin | Norrubrofusarin, CAS:3566-98-1, MF:C14H10O5, MW:258.23 g/mol | Chemical Reagent |
The ecology of wildlife parasitesâshaped by transmission dynamics, host spectra, and environmental persistenceâis a complex and rapidly evolving field. The One Health approach is not merely beneficial but essential for addressing the challenges posed by these pathogens. As climate change, habitat encroachment, and globalization continue to alter the interfaces between humans, animals, and ecosystems, the threat of parasitic zoonoses will only intensify [2] [9] [7]. Successfully mitigating this threat hinges on sustained collaboration across human medicine, veterinary science, ecology, and environmental science. Future efforts must prioritize integrated surveillance, the development of advanced predictive models like ENMs and network analyses, and innovative intervention strategies, such as drug repurposing, to safeguard the health of all species on the planet [14].
Zoonotic spillover, the process by which pathogens jump from animal reservoirs to human populations, represents a formidable threat to global health security. A staggering 60% of known infectious diseases in humans are of zoonotic origin, including major epidemics such as HIV, Ebola, and COVID-19 [15]. The growing pandemic prevention, preparedness and response (PPPR) agenda is heavily premised on the potential for such spillover events, with international agencies like the World Health Organization and World Bank proposing unprecedented funding levels exceeding $40 billion to address these threats [16]. The fundamental premise of this investment is that pandemic risk is rapidly increasing, driven particularly by anthropogenic environmental changes that facilitate pathogen transmission across species boundaries [16].
The One Health approach provides an essential framework for understanding and addressing these complex threats. Defined by the World Health Organization as "an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems," One Health recognizes the inextricable linkages between human, animal, and environmental health [1]. This approach is particularly crucial for addressing parasitic zoonoses, where the life cycles of pathogens often involve complex interactions between wildlife reservoirs, domestic animals, human populations, and changing environmental conditions. Effectively preventing and controlling zoonotic diseases requires collaboration across sectors responsible for human health, animal health (both domestic and wildlife), and the environment [17].
Despite widespread assertions that zoonotic outbreaks are increasing in frequency, the evidence base supporting these claims requires critical examination. As noted in recent scientific literature, "many of these assumptions are poorly supported by cited literature, over-simplifying a highly complex set of ecological interactions" [16]. This technical guide examines the current state of knowledge regarding climate change, habitat encroachment, and other anthropogenic drivers of spillover within the context of a One Health approach to wildlife parasitic zoonoses research.
Understanding the relative contribution of different anthropogenic factors to spillover risk enables targeted intervention strategies. The following tables synthesize available quantitative data on key drivers and their documented impacts on zoonotic disease emergence.
Table 1: Anthropogenic Drivers of Zoonotic Spillover and Documented Impacts
| Driver Category | Specific Mechanisms | Documented Impacts/Associations | Key Pathogens/Examples |
|---|---|---|---|
| Land Use Change | Deforestation, agricultural expansion, urban sprawl, habitat fragmentation | Cited as cause for >30% of new diseases since 1940 [15]; Concentrates species in smaller spaces, increasing inter-species transmission risk [15] | Ebola virus, Nipah virus, Hendra virus [16] |
| Climate Change | Range shifts of mammal species, glacial melt exposing ancient pathogens, temperature effects on vector survival | Estimated threefold increase in probability of extreme epidemics in coming decades [15]; New viral relationships between previously isolated species [15] | Avian influenza, vector-borne diseases [16] |
| Wildlife Trade & Industrial Animal Farming | High-density animal facilities, live animal markets, interspecies mixing at interfaces | Direct transmission pathways; Intermediate host development (e.g., poultry between waterfowl and humans) [15] | Avian influenza, SARS-CoV-2 (suspected) [15] |
Table 2: Economic and Health Impacts of Major Zoonotic Pandemics
| Pandemic Event | Estimated Economic Impact | Human Mortality/Morbidity | Spillover Origin |
|---|---|---|---|
| COVID-19 | $10-22 trillion (U.S. alone) [15] | Global mortality with lower case fatality rate but high transmissibility [15] | Suspected zoonotic origin, precise mechanism under investigation |
| HIV/AIDS | Not quantified in results | Approximately 40 million deaths globally since 1980s [15] | Chimpanzee to human spillover in 1920s [15] |
| Ebola Outbreaks | Not quantified in results | High case fatality rates (approximately 50%) [15] | Fruit bats of the Pteropodidae family [15] |
Analysis of these quantitative data reveals several critical patterns. First, land use change represents one of the most significant documented drivers of emerging zoonotic diseases. Second, the economic impacts of pandemics originating from spillover events can reach staggering levels, dwarfing potential investments in preventive measures. Third, climate change introduces novel and evolving pathways for spillover that may create unprecedented disease transmission dynamics. These quantitative relationships underscore the importance of developing robust predictive models and targeted surveillance systems for high-risk interfaces.
The Generalized One Health Framework provides a structured, five-step approach for implementing a One Health approach to zoonotic disease prevention and control. This framework can be applied at local, sub-national, national, regional, or international levels and includes a toolkit of existing resources matched to each step [17].
Table 3: Generalized One Health Framework (GOHF) for Zoonotic Disease Control
| Step | Objective | Key Activities | Primary Outcome Measures |
|---|---|---|---|
| 1. Engagement | Establish initial One Health collaborations around zoonotic disease control | Identify and engage stakeholders; Prioritize zoonotic diseases; Establish government support [17] | Prioritized list of zoonotic diseases; Government commitment to One Health approach [17] |
| 2. Assessment | Understand limitations and disparities in resources within the One Health system | Conduct joint sectoral assessments; Evaluate existing systems and capacities [17] | Documented strengths and weaknesses in each sector; Understanding of current situation [17] |
| 3. Planning | Develop plans and protocols that include and leverage all relevant One Health sectors | Develop strategic plans; Create technical protocols; Identify resource needs [17] | Multisectoral plans, protocols and procedures ready for implementation [17] |
| 4. Implementation | Implement programs that use a One Health approach | Implement plans; Conduct capacity building; Establish coordination mechanisms [17] | Operational One Health systems or zoonotic disease programs [17] |
| 5. Monitoring & Evaluation | Identify successes and improve upon weaknesses of One Health systems and/or programs | Track progress; Evaluate impact; Adapt and improve programs [17] | Improved capacity to control zoonotic diseases [17] |
The implementation of this framework requires specialized expertise and cross-sectoral coordination. Successful examples include Kenya's use of social network analysis to identify relevant stakeholders for Rift Valley fever programs, and Thailand's establishment of a cabinet-endorsed Coordinating Unit for One Health following H5N1 and H1N1 influenza outbreaks [17].
Emerging methodologies for predicting spillover risk combine ecological surveillance, molecular analysis, and computational modeling. The experimental workflow for spillover risk assessment involves multiple parallel approaches that converge to identify high-risk interfaces and pathogens.
Spillover Risk Assessment Workflow
This experimental workflow highlights the multidisciplinary nature of spillover risk assessment, integrating field ecology, laboratory science, and computational analytics. The outputs from this process directly inform preventive measures and policy decisions.
Environmental Impact Assessments (EIAs) represent a strategic policy mechanism for incorporating spillover risk consideration into development decisions. Currently, most EIA frameworks focus primarily on physical and ecological impacts without systematically addressing human health implications arising from altered disease dynamics [15]. Incorporating zoonotic risk assessment procedures into existing EIA frameworks represents a practical application of the One Health approach.
The legal and technical requirements for this integration vary across jurisdictions. In India, for example, the EIA Notification 2006 requires certain projects to undergo environmental clearance, but references to disease occur only in the context of hazardous substances, not habitat alteration [15]. Similarly, in the United States, the National Environmental Policy Act (NEPA) requires evaluation of impacts from major federal actions but does not explicitly address spillover risk [15]. Modification of these frameworks to include spillover analysis would require:
While practical challenges exist due to the inherent unpredictability of individual spillover events, research indicates that outbreaks follow predictable patterns, making risk assessment feasible [15]. Machine learning approaches are increasingly being used to predict potential spillovers and identify high-risk locations, with global hotspot maps already identifying tropical regions in the Americas, Asia, and Central Africa as areas of particular concern [15].
Implementing the experimental protocols described in this guide requires specialized reagents, tools, and methodologies. The following table outlines essential components of the spillover research toolkit.
Table 4: Research Reagent Solutions for Spillover Studies
| Reagent/Tool Category | Specific Examples | Function/Application | Technical Considerations |
|---|---|---|---|
| Genomic Sequencing Tools | Next-generation sequencing platforms; PCR assays; Primers for target pathogens | Pathogen discovery and characterization; Host range determination; Evolutionary analysis | Requires validation for diverse sample types; Must account for potential novel genetic sequences |
| Serological Assays | Multiplex bead arrays; ELISA kits; Neutralization assays | Detection of previous pathogen exposure; Seroprevalence studies in human and animal populations | Cross-reactivity between related pathogens can complicate interpretation |
| Cell Culture Systems | Primary cell cultures from diverse species; Organoid models; Air-liquid interface cultures | Simulation of cross-species transmission barriers; Study of host-pathogen interactions at cellular level | Difficult to establish for some wildlife species; May not fully recapitulate in vivo conditions |
| Environmental DNA Tools | eDNA extraction kits; Universal primers for vertebrate species; Bioinformatic pipelines | Detection of reservoir host distribution; Biodiversity monitoring in changing habitats | Requires careful contamination control; Complex mixture analysis challenging |
| Data Integration Platforms | One Health data sharing platforms; GIS software; Machine learning algorithms | Integration of ecological, epidemiological, and climatic data; Predictive modeling of spillover risk | Requires standardization across sectors; Privacy and data sharing considerations |
| Regaloside K | Regaloside K, MF:C18H24O11, MW:416.4 g/mol | Chemical Reagent | Bench Chemicals |
| 4-Demethyltraxillaside | 4-Demethyltraxillaside, MF:C27H34O12, MW:550.6 g/mol | Chemical Reagent | Bench Chemicals |
The effective application of these tools requires cross-disciplinary collaboration and data sharing. The Generalized One Health Framework emphasizes the importance of establishing coordination mechanisms that enable researchers from human health, animal health, and environmental sectors to collaborate effectively [17].
The complex interplay between climate change, habitat encroachment, and anthropogenic drivers of spillover requires a sophisticated, multidisciplinary research approach firmly grounded in One Health principles. While significant progress has been made in understanding the broad contours of spillover risk, critical knowledge gaps remain in predicting specific spillover events and developing effective interventions.
The scientific community faces the dual challenge of addressing legitimate concerns about potentially overstated claims of increasing spillover frequency while simultaneously advocating for evidence-based preventive measures [16]. This balance requires rigorous research methodologies, transparent data reporting, and critical evaluation of underlying assumptions about disease emergence dynamics.
Future research priorities should include: (1) longitudinal studies at high-risk human-wildlife interfaces; (2) development of validated predictive models incorporating climate, land use, and socioeconomic factors; (3) optimization of rapid response protocols for spillover events; and (4) economic analyses of the cost-effectiveness of preventive measures versus outbreak response. By addressing these priorities through a collaborative One Health framework, researchers can provide the evidence base needed to inform global health security policies and mitigate the threat of emerging zoonotic diseases.
The One Health approach recognizes the fundamental interconnectedness of human, animal, and environmental health. This is particularly critical for wildlife parasites, which represent a significant threat to global health, food security, and economic stability. Zoonotic parasitic diseases are infectious diseases caused by parasites that can be transmitted between animals and humans, and they account for more than 75% of human diseases [18]. The intricate relationships between human, animal, and environmental factors in disease transmission necessitates a collaborative, interdisciplinary strategy that transcends traditional disciplinary boundaries [18] [19].
Wildlife parasitology has long practiced integrative health research, even before the One Health concept gained popularity, by examining parasite transmission across host compartments, trophic levels, and the environment [19]. However, in a world with limited resources for scientific research and public health programming, it is impossible to study and manage all wildlife parasites with equal intensity. Therefore, systematic prioritization frameworks are essential to identify which parasites warrant immediate attention and investment based on their potential impact on human health, animal health, ecosystem integrity, and socioeconomic well-being [19].
Prioritization within a One Health context moves beyond a simple assessment of human health risk. It requires a balanced consideration of multiple factors affecting all components of the health triad. A wildlife parasite should be considered a priority if it poses a significant threat to any of the following: public health, agricultural productivity, food security, conservation of biodiversity, or the functioning of ecosystems [19]. Furthermore, the demographic and ecological context is critical. A parasite that is endemic and well-controlled in one region may be an emerging, high-priority threat in another due to differences in host populations, environmental conditions, or public health infrastructure [20]. The potential for emergence or re-emergence also elevates priority. Changes in climate, land use, wildlife migration patterns, and human behavior can alter transmission dynamics, causing previously localized or negligible parasites to become significant threats [21] [19].
To operationalize the core principles, a set of key questions can guide decision-makers. These questions, adapted from seminal One Health literature, provide a structured framework for evaluation [19]:
A robust example of a structured prioritization methodology is the One Health Zoonotic Disease Prioritization (OHZDP) tool, which has been successfully implemented in various contexts, including a pioneering workshop in Guyana [20]. This modified semi-quantitative tool employs a multi-step, consultative process involving multisectoral experts.
The process begins with a comprehensive hazard identification phase. This involves a scoping literature review of scientific databases and grey literature to generate an initial list of zoonotic pathogens. In the Guyana case, fifty zoonoses were identified for consideration [20]. Following this, clear inclusion and exclusion criteria are applied. For instance, the Guyana workshop focused on pathogens directly transmissible from Neotropical wildlife to humans, thereby excluding vector-borne diseases from the initial prioritization exercise [20].
The core of the process is a workshop where multisectoral experts from human, animal, and environmental health sectors gather. These experts use a structured set of prioritization criteria to score each zoonotic disease. The criteria are weighted to reflect their relative importance, and diseases are ranked based on their total weighted scores [20]. The final list of prioritized diseases, such as the top eight (tuberculosis, leptospirosis, gastroenteritis, rabies, coronavirus, orthopoxvirus, viral hemorrhagic fevers, and hepatitis) identified in Guyana, is then used to guide national policy, surveillance, and research funding [20].
Table 1: Key Steps in the OHZDP Process as Implemented in Guyana
| Step | Description | Output |
|---|---|---|
| 1. Pre-workshop Literature Review | Exhaustive search of peer-reviewed publications and scholarly reports on zoonotic pathogens from wildlife in the region. | A preliminary list of potential zoonotic diseases (e.g., 50 diseases in Guyana) [20]. |
| 2. Hazard Identification & Criteria Setting | Application of inclusion/exclusion criteria and establishment of weighted prioritization criteria. | A refined list of zoonoses and a agreed-upon scoring framework. |
| 3. Multisectoral Expert Workshop | Engagement of experts from human health, veterinary medicine, ecology, wildlife management, and food safety. | A collaborative environment for discussion and scoring [20]. |
| 4. Semi-Quantitative Scoring & Ranking | Experts score diseases based on weighted criteria using a defined scale (e.g., one-to-five). | A ranked list of zoonotic diseases in order of relative importance [20]. |
| 5. Final Prioritization & Output | Discussion of tool output and consensus-building to finalize the priority list. | A final list of priority zoonoses to guide national policy and research [20]. |
Effective prioritization relies on high-quality surveillance data. The methods for collecting and processing samples from wildlife are critical for accurate parasite detection and identification.
Sample Collection and Identification: Sampling can be invasive (trapping, carcass collection) or non-invasive (scat collection, camera traps). Non-invasive methods are increasingly used but require careful species identification of the host, for instance through molecular scatology, to avoid misidentification bias [22].
Sample Preservation and Analysis: The preservation method must align with the analysis goals. Fresh samples are ideal, but room-temperature storage leads to DNA degradation after 24 hours. Freezing at -20°C is suitable for molecular analysis but may destroy certain larval stages needed for morphological identification (e.g., for Ancylostomatidae and Strongyloididae, which require the Baermann technique) [22]. For morphological study of adult helminths, specimens should be relaxed in warm saline before preservation to prevent muscle contraction that distorts taxonomic structures [22].
Table 2: Key Research Reagents and Materials for Wildlife Parasitology
| Reagent/Material | Function/Application | Considerations |
|---|---|---|
| Ethanol (70-96%) | Preservation of tissue and parasite samples for molecular and morphological analysis. | Concentration depends on downstream use (e.g., DNA vs. morphology) [22]. |
| Formalin (10%) | Fixation of tissue samples and parasites for histological examination. | Excellent for preservation of morphology but not suitable for subsequent DNA analysis [22]. |
| Phosphate-Buffered Saline (PBS) | Washing and relaxing fresh helminths collected from feces or tissues. | Relaxing worms in warm PBS prevents contraction of muscle fibers, aiding identification [22]. |
| Sieves (100â200 µm) | Separation of macroscopic parasites from gut content during necropsy. | Used in the "shaking in a vessel technique" to isolate parasites from digested material . |
| FTA Cards | Room-temperature storage and preservation of DNA from blood or tissue samples. | Useful for field collection and transport when refrigeration is not available. |
| Baermann Apparatus | Concentration and isolation of live larvae from fecal samples. | Requires fresh, unpreserved samples as larvae need to be motile for the technique to work [22]. |
The following workflow diagram summarizes the key decision points in the sample collection and analysis process for wildlife parasites.
Diagram 1: Wildlife Parasite Sample Workflow
Translating prioritization criteria into a actionable score requires a structured system. The following diagram illustrates the logical flow of a prioritization exercise, from assessing a parasite against key criteria to determining its overall priority level for One Health attention.
Diagram 2: Parasite Prioritization Logic Flow
The framework of guiding questions can be effectively illustrated with the example of Toxoplasma gondii in the Canadian Arctic. This case shows how a parasite can be prioritized based on multifaceted impacts on a One Health system [19].
This multi-faceted impact profile, touching on human health, cultural safety, and environmental mystery, makes T. gondii a high-priority parasite for One Health action in the Arctic.
The prioritization of wildlife parasites for One Health attention is not an academic exercise but a practical necessity for the efficient allocation of resources in a world of evolving health threats. A successful framework must be semi-quantitative, incorporating weighted criteria to allow for objective ranking, yet flexible enough to accommodate regional variations in disease impact and capacity. As demonstrated by the OHZDP process in Guyana and the assessment of T. gondii in the Arctic, the engagement of a wide range of expertsâfrom epidemiologists and veterinarians to ecologists and social scientistsâis fundamental to building a comprehensive and legitimate priority list. The resulting list is a powerful tool for guiding national and international policy, shaping future research agendas, and ultimately building a more robust global defense against the complex threat of zoonotic parasitic diseases.
This whitepaper explores two distinct parasitic zoonosesâToxoplasmosis in Arctic ecosystems and Cystic Echinococcosis (CE) at domestic-wildlife interfacesâthrough the integrative lens of the One Health framework. The One Health approach recognizes that the health of people is closely connected to the health of animals and our shared environment [2]. Using these case studies, we demonstrate how transdisciplinary collaborations and sophisticated epidemiological tools are essential for understanding transmission dynamics, assessing economic and health impacts, and developing effective control strategies for parasitic zoonoses of global significance.
Parasitic zoonoses represent a significant threat to global health, with profound economic and social consequences. The One Health approach is a collaborative, multisectoral, and transdisciplinary strategy that operates at local, regional, national, and global levels to achieve optimal health outcomes by recognizing the interconnection between people, animals, plants, and their shared environment [2]. This framework is particularly critical for combating zoonotic diseases, which account for over 60% of emerging infectious diseases in humans [7]. The complex life cycles of parasites like Toxoplasma gondii and Echinococcus granulosus involve multiple hosts and environmental reservoirs, making their control a quintessential One Health challenge requiring integrated surveillance, intervention, and research across human, animal, and environmental health domains.
Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, has a heteroxenous life cycle in which felines act as definitive reservoirs [23]. The parasite can only sexually reproduce in felids, which excrete massive numbers of environmentally-resistant oocysts via feces [23]. Its presence in the Arctic is particularly enigmatic, as felids are rare in these regions [24]. Recent hypotheses suggest that migratory geese might act as vectors, transporting T. gondii from temperate overwintering grounds into Arctic food webs [25]. These geese, along with oocysts potentially transported by oceanic currents, act as 'parasite pollutants' moving from land to sea and back again in Arctic ecosystems [24].
Seroprevalence studies in Arctic-nesting geese provide critical insights into parasite circulation. Occupancy modeling techniques, which account for imperfect pathogen detection, have enhanced estimation accuracy.
Table 1: Toxoplasma gondii Seroprevalence in Arctic-Nesting Geese
| Species | Location | Seroprevalence (Probability) | Diagnostic Methods |
|---|---|---|---|
| Ross's Geese | Karrak Lake, Nunavut, Canada | 0.39 | IFAT, DAT |
| Lesser Snow Geese | Karrak Lake, Nunavut, Canada | 0.36 | IFAT, DAT |
Abbreviations: IFAT - Indirect Fluorescent Antibody Test; DAT - Direct Agglutination Test [25]
Furthermore, exposure in polar bears is increasing, linked to climate change-induced behavioral shifts and increased time on land in this rapidly warming region [24]. These findings position polar bears and geese as valuable sentinel species for monitoring ecosystem health and parasite pollution in the Arctic.
Sample Collection: Blood samples are collected from harvested geese during migration seasons on filter paper strips. For marine mammals and polar bears, sampling occurs during scientific expeditions or through indigenous hunter harvest programs [25] [24].
Serological Analysis:
Genetic Analysis: Tissue cysts from infected animals are characterized using PCR-RFLP markers to identify T. gondii genotypes and track potential sources [23]. This helps distinguish between recently introduced strains versus established Arctic lineages.
The following diagram illustrates the complex pathways through which T. gondii enters and circulates in Arctic ecosystems:
Cystic Echinococcosis (CE), or hydatid disease, is a neglected zoonotic disease caused by the larval stage of the tapeworm Echinococcus granulosus [26]. The parasite maintains a domestic life cycle between definitive hosts (dogs and other canids) and intermediate hosts (livestock such as sheep, cattle, and goats) [27]. Humans act as accidental intermediate hosts, acquiring infection through ingestion of parasite eggs excreted in canid feces, often through contaminated food, water, or soil [26] [28]. The highest prevalence occurs in sheep-raising rural communities where close contact exists between dogs, livestock, and humans [29] [28].
CE imposes a substantial health and economic burden worldwide, with the 2015 WHO Foodborne Disease Burden Epidemiology Reference Group estimating it causes 19,300 deaths and approximately 871,000 disability-adjusted life-years (DALYs) globally each year [26]. The economic impact is multifaceted, encompassing both direct costs from organ condemnation in livestock and extensive human treatment costs.
Table 2: Cystic Echinococcosis Prevalence and Economic Impact in Selected Studies
| Location | Host Species | Prevalence | Organs Most Affected | Economic Impact |
|---|---|---|---|---|
| Migori County, Kenya [27] | Cattle | 5.3% | Lungs, Liver | $152,003/year direct losses |
| Migori County, Kenya [27] | Goats | 2.0% | Lungs, Liver | $152,003/year direct losses |
| Migori County, Kenya [27] | Sheep | 0.1% | Lungs, Liver | $152,003/year direct losses |
| Basrah, Iraq [29] | Humans | 4.5/100,000 annual incidence | Liver (51.7%), Lungs (28.3%) | N/A |
Epidemiological studies have identified key risk factors associated with CE transmission at domestic-wildlife interfaces:
A knowledge-practice gap exacerbates transmission in endemic areas. In Basrah, Iraq, 72% of surgically treated CE patients had heard of hydatid disease, but 57% were unaware of transmission routes, and 86% did not boil drinking water [29]. This highlights critical gaps in One Health education efforts.
Abattoir Surveillance Protocol:
Clinical Diagnostic Protocol:
The following diagram illustrates the transmission cycle of E. granulosus and key intervention points:
Table 3: Essential Research Reagents and Their Applications
| Reagent/Assay | Application | Specifications | Research Utility |
|---|---|---|---|
| Indirect Fluorescent Antibody Test (IFAT) | Detection of T. gondii antibodies in serum/eluates | High sensitivity, species-specific conjugates required | Seroprevalence studies in wildlife and sentinel species [25] |
| Direct Agglutination Test (DAT) | T. gondii antibody detection | Simple format, less ambiguous results | Complementary serological assay for wildlife [25] |
| PCR-RFLP Markers | Genotyping of T. gondii and Echinococcus strains | 10+ markers for comprehensive genotyping | Molecular epidemiology and source tracking [23] |
| EG95 Recombinant Antigen | E. granulosus vaccine development | Commercial production in China and Argentina | Livestock vaccination to interrupt transmission [26] |
| Praziquantel | Canid deworming for Echinococcus control | Minimum 4 treatments annually | Definitive host intervention to reduce environmental contamination [26] |
| Ultrasonography with WHO Classification | Human CE diagnosis and staging | Standardized imaging classification (CE1-CE5) | Clinical management and epidemiological studies [26] |
| Withasomniferolide A | Withasomniferolide A|For Research Use Only | Withasomniferolide A is a withanolide from Withania somnifera for research. This product is for laboratory research purposes only. | Bench Chemicals |
| Eupaglehnin C | Eupaglehnin C|RUO | Eupaglehnin C is a natural germacrane-type sesquiterpenoi with research applications. This product is for Research Use Only (RUO). Not for human use. | Bench Chemicals |
A comprehensive One Health research approach requires integration of multiple methodologies:
Epidemiological Modeling: Statistical approaches like occupancy modeling account for imperfect detection in prevalence studies, while network analysis explores zoonotic agent sharing among sources [25] [30].
Molecular Epidemiology: Genetic characterization of parasites using multilocus genotyping tracks transmission pathways and identifies emerging strains [23].
Socio-behavioral Research: Knowledge, Attitude, and Practice (KAP) surveys identify critical gaps in public awareness to tailor education programs [29].
These case studies demonstrate that despite different ecological settingsâremote Arctic ecosystems versus pastoral domestic-wildlife interfacesâeffective control of parasitic zoonoses requires common One Health strategies:
Both systems require breaking down disciplinary silos. Toxoplasmosis control necessitates collaboration between wildlife biologists, oceanographers, veterinarians, and public health officials [24] [23], while CE control involves veterinarians, physicians, agricultural workers, and social scientists [29] [28]. The zoonotic web concept emphasizes that infectious agents circulate in complex networks requiring integrated approaches [30].
Both cases highlight the value of sentinel speciesâgeese and polar bears for Arctic toxoplasmosis, and livestock for CEâas early warning systems for ecosystem health threats and transmission dynamics [25] [24].
Control strategies must be adapted to local ecological and social contexts. For CE, a combination of dog deworming, livestock vaccination with EG95, abattoir hygiene, and public education could eliminate human transmission within a decade [26]. For Arctic toxoplasmosis, understanding changing transmission pathways in warming climates is paramount [24].
Both diseases impose substantial economic burdensâCE costs an estimated $3 billion annually globally from human treatment and livestock losses [26], while toxoplasmosis costs nearly $3 billion annually in the USA alone from foodborne illness [23]. One Health economics must account for these cross-sectoral impacts to justify integrated control programs.
Toxoplasmosis in Arctic ecosystems and Cystic Echinococcosis at domestic-wildlife interfaces exemplify the complex challenges at the human-animal-environment interface. Through these case studies, we demonstrate that the One Health approach is not merely a conceptual framework but an essential practical strategy for understanding and controlling parasitic zoonoses. Future research should focus on enhancing surveillance networks, developing novel interventions, and strengthening transdisciplinary collaborations to address these persistent and emerging threats to global health. The development of locally-relevant One Health strategies, informed by robust epidemiological data and community engagement, remains critical for reducing the burden of these neglected parasitic diseases.
Integrated surveillance systems are critical for early detection and management of wildlife parasitic zoonoses within a One Health framework. These systems combine molecular diagnostics, strategic use of sentinel species, and environmental monitoring to provide a comprehensive understanding of pathogen dynamics at the human-animal-environment interface. This technical guide examines current methodologies, experimental protocols, and analytical frameworks that enable researchers to effectively monitor, predict, and mitigate zoonotic disease threats. By synthesizing the latest advances in surveillance technologies and approaches, this review provides a foundation for developing robust, multi-sectoral surveillance networks that can adapt to evolving zoonotic challenges in an increasingly interconnected world.
The One Health approach recognizes that the health of humans, animals, and ecosystems are interconnected and interdependent [2]. This integrated perspective is particularly crucial for addressing parasitic zoonoses, which account for a significant proportion of emerging infectious diseases [31] [30]. Integrated surveillance systems form the backbone of effective One Health implementation, enabling early detection, timely response, and evidence-based control of zoonotic pathogens [32] [33].
The fundamental principle of One Health surveillance lies in breaking down traditional silos between human, animal, and environmental health sectors. This requires collaborative, multisectoral, and transdisciplinary approaches that work across local, regional, national, and global levels [2]. The complex ecology of zoonotic diseases necessitates surveillance strategies that capture pathogen dynamics across multiple hosts, vectors, and environmental reservoirs [30]. By integrating data streams from these diverse sources, surveillance systems can provide early warnings of spillover events, track pathogen evolution and spread, and inform targeted interventions [32] [33].
Despite growing recognition of its importance, operationalizing integrated surveillance faces significant challenges. These include professional and budgetary silos, differences in awareness and priority between sectors, lack of standardized data sharing protocols, and fragmented community engagement [34] [33]. Furthermore, surveillance systems have historically focused on human and domestic animal health, often neglecting wildlife and environmental components [34]. This guide addresses these challenges by providing a comprehensive framework for implementing integrated surveillance systems that effectively capture the complexity of zoonotic disease transmission.
Molecular diagnostics have revolutionized infectious disease surveillance by enabling rapid, sensitive, and specific detection of pathogens. Metagenomic sequencing (mNGS) represents a particularly transformative approach for One Health surveillance. Unlike traditional diagnostic methods that target specific known pathogens, mNGS allows for unbiased detection of a broad spectrum of infectious agents without prior knowledge of the causative organism [32]. The methodology involves direct sequencing of nucleic acids from clinical, animal, or environmental samples, followed by sophisticated bioinformatic analysis to identify pathogenic sequences [32] [35].
The basic workflow of metagenomic analysis comprises five critical steps: (1) genome enrichment to increase pathogen nucleic acid concentration, (2) genomic DNA extraction, (3) metagenomic DNA library construction, (4) target gene screening, and (5) product activity expression [32]. This approach has proven particularly valuable for diagnosing complex central nervous system infections and detecting co-infections that might be missed by targeted assays [32]. In One Health contexts, mNGS enables simultaneous surveillance of bacterial, viral, fungal, and parasitic pathogens across human, animal, and environmental samples, providing unprecedented insights into pathogen diversity and transmission dynamics.
Polymerase chain reaction (PCR)-based methods remain fundamental to molecular surveillance systems, with ongoing advancements enhancing their utility. Real-time quantitative PCR (qPCR) and reverse transcription qPCR (RT-qPCR) provide sensitive detection and quantification of pathogen load, which is crucial for monitoring disease progression and transmission risk [36]. These techniques have been widely deployed in environmental surveillance, including wastewater monitoring, where they enable community-level assessment of pathogen circulation [36]. The development of portable, rapid PCR platforms has further expanded the application of molecular diagnostics to field settings, enabling near real-time surveillance in remote locations with limited infrastructure [32].
Implementing molecular diagnostics in integrated surveillance requires careful consideration of sampling strategies, analytical protocols, and quality assurance measures. For comprehensive pathogen detection, the following protocol provides a framework for metagenomic sequencing in One Health surveillance:
Sample Collection and Processing:
Library Preparation and Sequencing:
Bioinformatic Analysis:
Table 1: Key Molecular Reagents for One Health Surveillance
| Reagent Category | Specific Examples | Applications in Surveillance |
|---|---|---|
| Nucleic Acid Extraction Kits | QIAamp DNA/RNA Kits, PowerSoil DNA Kit | Extraction from clinical, environmental, and animal samples |
| Library Preparation Kits | Illumina DNA Prep, Nextera XT | Metagenomic library construction for NGS |
| Enzymes & Master Mixes | Q5 High-Fidelity DNA Polymerase, OneTaq RT-PCR Mix | Amplification and detection of pathogen sequences |
| Probes & Primers | Custom TaqMan assays, Pan-pathogen primers | Targeted detection of specific zoonotic pathogens |
| Sequencing Reagents | Illumina SBS chemistry, Nanopore R9 flow cells | Platform-specific sequencing of prepared libraries |
| Bioinformatic Tools | Kraken2, BLAST, CZ-ID, IDseq | Taxonomic classification and pathogen identification |
The sensitivity and specificity of molecular surveillance can be enhanced through targeted enrichment strategies. Hybridization-based capture using pathogen-specific probes increases the sensitivity for detecting low-abundance pathogens in complex samples [32]. This approach is particularly valuable for monitoring specific zoonotic threats or conducting focused surveillance in high-risk interfaces. For high-throughput screening, multiplexed PCR panels enable simultaneous detection of multiple pathogens from a single sample, providing efficient surveillance of common zoonotic agents [32].
Sentinel species are organisms that respond measurably and in a timely manner to environmental changes or pathogen presence, providing early warnings of health threats to other species, including humans [35]. The strategic deployment of sentinels represents a powerful approach for monitoring zoonotic pathogens in hard-to-reach environments and complex ecosystems. Effective sentinel species function as "virus collectors" that can accumulate and amplify pathogen signals, making them valuable components of integrated surveillance systems [35].
Selecting appropriate sentinel species requires careful consideration of ecological and physiological factors. Key selection criteria include:
Top predators and scavengers often make excellent sentinels due to their position in food webs, which exposes them to pathogens accumulating through trophic transfer [35]. Similarly, species with wide geographic ranges provide valuable data across diverse locations and ecosystems, while those with specific ecological niches offer insights into specialized environments [35].
Implementing sentinel-based surveillance requires standardized protocols for sample collection, processing, and analysis. The following workflow outlines a comprehensive approach to sentinel surveillance:
Sentinel Selection and Monitoring:
Sample Collection and Analysis:
Data Integration and Interpretation:
Table 2: Promising Sentinel Species for Zoonoses Surveillance
| Ecosystem Type | Candidate Sentinel Species | Target Pathogens/Zoonoses | Surveillance Advantages |
|---|---|---|---|
| Terrestrial Forests | Army ants (Dorylus spp.), Top feline predators | Cressdnaviricota, Zoonotic viruses | Wide foraging range, prey accumulation [35] |
| Polar Regions | Snowy sheathbill (Chionis albus) | Sapovirus, Gammaherpesvirus | Migration patterns, scavenging behavior [35] |
| Urban Environments | Birds (crows, pigeons), Rodents | West Nile virus, Leptospirosis | Proximity to human populations, accessibility [2] |
| Aquatic Systems | Filter-feeding mollusks, Predatory fish | Waterborne pathogens, Toxoplasma | Bioaccumulation, filtration capacity [35] |
| Agricultural Lands | Livestock, Peridomestic wildlife | Zoonotic influenza, Brucellosis | Interface with domestic animals and humans [30] |
The effectiveness of sentinel-based surveillance depends on proper validation. Critical validation steps include determining whether the viral diversity detected in sentinels accurately reflects that circulating in the ecosystem, understanding how long pathogens persist in sentinels, and establishing the representativeness of sentinel findings across spatial and temporal scales [35]. Advanced techniques such as diet metabarcoding can help identify the sources through which sentinels accumulate pathogens, while biologging technology provides insights into their movement patterns and exposure risks [35].
Environmental monitoring provides critical complementary data to clinical and animal surveillance, offering population-level insights into pathogen circulation without individual testing. Wastewater-based epidemiology (WBE) has emerged as a particularly powerful tool for monitoring community health, with demonstrated effectiveness during the COVID-19 pandemic [36]. WBE involves analyzing wastewater to detect pathogens shed in human feces, providing a cost-effective, non-invasive method for community-wide surveillance that captures both symptomatic and asymptomatic infections [36].
The technical workflow for WBE includes:
WBE has expanded beyond SARS-CoV-2 to monitor diverse pathogens including influenza, norovirus, antimicrobial resistance genes, and zoonotic parasites [36]. The approach is particularly valuable for tracking pathogens with high rates of asymptomatic infection, as it provides an unbiased measure of community transmission. Recent technological advances have enhanced WBE applications, including the development of automated sampling systems, improved concentration methods for different pathogen types, and sophisticated data normalization techniques that account for wastewater composition and flow dynamics [36].
Beyond wastewater, comprehensive environmental surveillance incorporates multiple sampling matrices to capture pathogen dynamics across different reservoirs. Aerobiology - the study of airborne microorganisms - provides insights into the transmission of respiratory pathogens, while surface microbiome analysis examines high-touch areas to assess pathogen persistence in built environments [36]. Integrating these approaches with WBE creates a multidimensional surveillance system that enhances early detection capabilities and provides cross-validation of findings.
Effective environmental surveillance programs incorporate:
The integration of environmental surveillance with other data streams creates a powerful early warning system. For example, detecting avian influenza in wastewater before clinical cases emerge allows for proactive public health interventions [36]. Similarly, monitoring antimicrobial resistance genes in environmental samples provides insights into the dissemination of resistance mechanisms across human, animal, and environmental compartments [37] [36].
Developing effective integrated surveillance requires systematic frameworks that bridge sectoral and disciplinary boundaries. The One Health Joint Plan of Action (OH JPA) Theory of Change provides a structured approach, organized across three pathways: (1) policy, legislation, advocacy and financing; (2) organizational development, implementation and sectoral integration; and (3) data, evidence and knowledge [34]. This framework emphasizes that successful integration requires attention not only to technical capabilities but also to governance structures, funding mechanisms, and knowledge-sharing practices.
A systematic approach to developing One Health surveillance systems involves six key steps [33]:
The "zoonotic web" concept provides a valuable analytical framework for understanding and mapping complex relationships between zoonotic agents, their hosts, vectors, food, and environmental sources [30]. This network-based approach reveals key interfaces for transmission and identifies influential nodes that disproportionately affect disease dynamics. Network analysis applied to zoonotic webs can identify communities of zoonotic agent sharing and pinpoint critical intervention points [30].
Integrating diverse data streams from human, animal, and environmental surveillance requires sophisticated analytical approaches and interoperable data systems. Multiple-correspondence analysis (MCA) and hierarchical cluster analysis (HCA) can identify patterns and relationships across disparate data types, facilitating the development of surveillance system typologies [37]. Similarly, network analysis applied to zoonotic interaction data can reveal community structures and identify central actors in disease transmission [30].
Key considerations for data integration include:
Table 3: Metrics for Evaluating Integrated Surveillance Systems
| Evaluation Dimension | Specific Metrics | Data Sources |
|---|---|---|
| System Performance | Timeliness, Sensitivity, Specificity, Predictive value | Surveillance records, Laboratory data |
| Coverage & Representativeness | Geographic coverage, Population representation, Pathogen scope | Sampling records, Population data |
| Integration Level | Number of sectors involved, Data sharing protocols, Joint analyses | System documentation, Stakeholder interviews |
| Impact & Utility | Outbreaks detected, Interventions informed, Policy changes | Response records, Policy documents |
| Resource Efficiency | Cost per sample, Cost per outbreak detected, Staff time | Financial records, Activity logs |
The effectiveness of integrated surveillance ultimately depends on its ability to inform public health action. This requires not only technical capabilities but also established pathways for communication, decision-making, and intervention. Regular exercises and simulations help identify bottlenecks in these pathways before actual emergencies, building muscle memory for coordinated response [33]. Furthermore, engaging communities in surveillance activities enhances acceptability, provides local knowledge, and strengthens the sustainability of surveillance systems [34] [33].
Integrated surveillance systems that combine molecular diagnostics, sentinel species, and environmental monitoring represent a powerful approach for addressing wildlife parasitic zoonoses within a One Health framework. The synergistic application of these components provides complementary data streams that enable more comprehensive understanding of zoonotic disease dynamics than any single approach could achieve independently. Molecular technologies continue to advance the sensitivity, speed, and scope of pathogen detection, while strategic use of sentinels provides windows into hard-to-reach ecosystems. Environmental monitoring, particularly wastewater surveillance, offers population-level insights that capture both human and animal contributions to pathogen circulation.
Implementing effective integrated surveillance requires addressing significant challenges, including breaking down sectoral silos, developing interoperable data systems, and securing sustainable funding. The frameworks and protocols outlined in this guide provide a roadmap for overcoming these barriers and establishing surveillance systems that are greater than the sum of their parts. As anthropogenic changes continue to alter interactions between humans, animals, and ecosystems, the importance of such integrated approaches will only grow. By investing in robust, multi-sectoral surveillance networks today, we can build resilience against the zoonotic threats of tomorrow.
Future directions for integrated surveillance include the expanded application of novel technologies such as CRISPR-based diagnostics, environmental DNA (eDNA) monitoring, and artificial intelligence for pattern recognition in complex datasets. Additionally, there is growing recognition of the need to more fully incorporate plant health into One Health surveillance, given the interconnectedness of agricultural systems, ecosystem health, and human nutrition. As these technologies and frameworks evolve, they will further enhance our ability to detect, understand, and mitigate zoonotic threats at their source, ultimately protecting human, animal, and ecosystem health through truly integrated approaches.
Zoonoses, diseases naturally transmissible between animals and humans, constitute a major threat to global health, accounting for approximately 60% of all human infectious diseases and 75% of emerging infectious diseases [38]. The complex ecology of these diseases, involving multiple host species, environmental reservoirs, and transmission pathways, demands a sophisticated analytical approach. The One Health framework, which integrates human, animal, and environmental health, is essential for untangling these complexities [5]. This technical guide explores the application of network analysis to model "zoonotic webs"âthe intricate relationships between zoonotic agents, their hosts, vectors, and environmental sources [30]. For researchers and drug development professionals, this approach provides a powerful methodology for identifying critical control points and optimizing surveillance and intervention strategies for wildlife parasitic zoonoses.
Traditional zoonosis research often focuses on direct host-pathogen interactions. However, a comprehensive One Health view requires mapping all potential transmission routes. A systematic analysis of emerging zoonotic diseases identified five broad transmission pathway categories [39]:
The relative importance of these pathways varies significantly depending on the underlying drivers of disease emergence, such as land-use change, agricultural intensification, or bushmeat consumption [39]. This variability underscores the need for targeted, context-specific surveillance strategies.
The "zoonotic web" is a network-based conceptual model akin to an ecological food web [30]. It represents the complex network of relationships among all actors in a zoonotic system: zoonotic agents (pathogens), their vertebrate hosts (including humans, wildlife, and livestock), invertebrate vectors, food products, and environmental sources. This concept moves beyond simple linear transmission chains to model the multi-source, multi-agent systems that characterize real-world zoonotic disease dynamics. Analyzing this web allows researchers to identify highly connected nodes and interfaces where pathogen spillover is most probable, thereby informing more effective and preemptive One Health strategies.
Constructing a robust zoonotic web requires systematically compiled data on zoonotic interactions. The following protocol, adapted from a national-scale study, ensures comprehensive and structured data collection [30].
Once compiled, the data forms a bipartite network, which can be transformed and analyzed using various metrics.
The ultimate goal of network analysis is to identify Critical Control Points (CCPs)âspecific points, steps, or interfaces in the zoonotic web where a hazard can be prevented, eliminated, or reduced to acceptable levels. In the context of the One Health approach, CCPs often emerge at key interfaces [38]:
Network analysis quantitatively identifies these CCPs by highlighting nodes with high betweenness centrality and interfaces with high spillover probability, such as human-cattle and human-food interfaces [30].
Data synthesis is critical for translating network models into actionable insights. The tables below summarize key quantitative findings from foundational studies in the field.
Table 1: Proportion of Zoonotic EIDs Transmitted by Different Pathways (Equal Weighting) [39]
| Transmission Pathway | Percentage of Zoonotic Pathogens |
|---|---|
| Oral Transmission | 42% |
| Vector-Borne | 42% |
| Airborne Transmission | 36% |
| Direct Contact | 29% |
| Contaminated Environment/Fomite | 24% |
Note: Percentages exceed 100% as many pathogens can be transmitted via multiple pathways.
Table 2: Zoonotic Agent Sharing Communities in a National Network [30]
| Community / Cluster | Key Associated Sources | Drivers and Characteristics |
|---|---|---|
| Livestock-Associated | Cattle, Chicken, Pork/Beef Meat | Driven by anthropogenic activities and high connectivity of domesticated animals in the web. |
| Wildlife-Associated | Wild boar, Rodents, Certain Tick species | Driven by sylvatic cycles and natural host-pathogen relationships. |
| Food-Environment | Fresh produce, Water, Soil | Driven by environmental contamination and fecal-oral transmission routes. |
| Multi-Host Generalist | Human, Dogs, Cats | Characterized by highly promiscuous zoonotic agents with broad host ranges. |
Implementing a network analysis for zoonotic diseases requires a combination of analytical tools and laboratory capacities. The following toolkit outlines essential resources.
Table 3: Research Reagent Solutions for Zoonotic Web Studies
| Item / Tool | Function / Application |
|---|---|
| One Health Zoonotic Disease Prioritization (OHZDP) Tool | A structured process to engage multisectoral partners in prioritizing zoonotic diseases of greatest concern for a specific region using a mixed-methods approach [40]. |
| One Health Systems Mapping & Analysis Resource Toolkit (OH-SMART) | A workshop-based tool for mapping multisectoral coordination and collaboration, and for developing action plans to improve One Health systems for disease control [40]. |
| PCR Assays (Broad-Range & Specific) | For pathogen discovery and identification in host, vector, and environmental samples. Broad-range primers (e.g., 16S rRNA for bacteria) enable detection of unexpected agents. |
| Enzyme-Linked Immunosorbent Assay (ELISA) | To detect pathogen exposure (antibodies) in host species, providing data on past infection and seroprevalence across the network. |
| Next-Generation Sequencing (NGS) | For whole-genome sequencing of isolated pathogens, enabling high-resolution analysis of transmission dynamics and strain relatedness across the network. |
| Geographic Information Systems (GIS) | To georeference data on host, pathogen, and environmental factors, allowing for spatial analysis and mapping of network nodes and links. |
| Network Analysis Software (e.g., R/igraph, Gephi) | To construct, visualize, and analyze the bipartite and projected networks, and to calculate centrality and community structure metrics. |
| 14-Episinomenine | 14-Episinomenine, MF:C19H23NO4, MW:329.4 g/mol |
| Gambogic acid B | Gambogic Acid B |
A powerful approach for operationalizing research findings involves integrating two key tools in sequence [40]:
This integrated protocol ensures that network analysis findings are translated into practical, prioritized, and collaboratively owned interventions.
A cross-sectional study of Guinea's regional One Health platforms provides a real-world example of assessing system readiness. The evaluation, based on the Africa CDC assessment tool, scored performance across seven key indicators, revealing an overall national performance score of 41%, indicating limited implementation [5]. Radar chart analysis showed significant regional disparities and major weaknesses in mobilizing material resources (scoring only 9%), despite stronger performance in legislation in the capital region, Conakry (scoring 89%) [5]. This case underscores that technical network analysis must be coupled with robust institutional capacity for effective One Health action.
The One Health approach, which recognizes the interconnection between human, animal, and environmental health, provides a critical framework for addressing the unique challenges of wildlife parasitic zoonoses [2]. These diseases, transmitted from wild animals to humans, pose significant and evolving threats to global health security, intensified by climate change, habitat encroachment, and increased human-wildlife interfaces [41] [30]. Traditional drug discovery pathways are often economically non-viable for these neglected diseases due to limited market incentives [14] [42]. Computational biology offers a powerful suite of tools to overcome these barriers, enabling the rapid, cost-effective identification and optimization of therapeutic interventions through virtual screening, Pharmacokinetic-Pharmacodynamic (PK/PD) modeling, and strategic drug repurposing [43] [44]. This technical guide explores the integration of these computational methodologies within a One Health context, providing researchers with advanced protocols to accelerate the development of treatments for parasitic zoonoses, thereby protecting human populations while conserving wildlife and ecosystem health.
Virtual screening has emerged as an indispensable first step in modern drug discovery, allowing researchers to computationally screen billions of chemical compounds to identify potential hits before costly wet-lab experiments [43] [44]. Its importance is magnified in the One Health context, where resource constraints for neglected zoonotic diseases demand highly efficient discovery pipelines.
RosettaVS, a highly accurate structure-based virtual screening method, exemplifies recent advancements. This method outperforms other state-of-the-art approaches by successfully modeling receptor flexibility, a critical factor for accurately predicting binding poses and affinities [43]. The platform operates through two specialized docking modes:
To manage the computational expense of screening billion-compound libraries, active learning techniques are integrated into the screening workflow. These techniques simultaneously train a target-specific neural network during docking computations to intelligently select the most promising compounds for expensive docking calculations [43].
The following diagram illustrates the integrated virtual screening workflow, incorporating both traditional and AI-accelerated approaches for parasitic zoonoses drug discovery:
Protocol Details:
Target Preparation: Obtain the 3D protein structure of the parasitic zoonotic target (e.g., via X-ray crystallography, homology modeling). Define the binding site coordinates. Pre-process the structure by adding hydrogen atoms, assigning partial charges, and optimizing side-chain conformations [43].
Compound Library Curation: Compile a diverse chemical library. For parasitic diseases, consider libraries enriched with known anti-parasitic compounds or natural products. Common libraries include ZINC, ChEMBL, or proprietary collections. Pre-process compounds by generating 3D conformations, enumerating tautomers, and applying chemical filters for drug-likeness [43] [44].
VSX Screening (Initial Triage): Run the express docking mode against the entire library. This step uses reduced sampling and rigid receptor approximations to rapidly eliminate >99% of non-promising compounds. Typical parameters: 5-10 docking poses per compound, limited side-chain flexibility [43].
Active Learning Cycle: Train a convolutional neural network (CNN) on the fly using docking scores and molecular descriptors from the VSX output. The CNN iteratively predicts which unexplored regions of chemical space are most likely to contain high-affinity binders, directing subsequent docking efforts [43].
VSH Re-docking (Final Ranking): Subject the top 0.1-1% of compounds from the active learning cycle to high-precision docking. This step includes full side-chain flexibility and limited backbone movement. Use the improved RosettaGenFF-VS scoring function, which combines enthalpy (ÎH) calculations with entropy (ÎS) estimates for more accurate ranking [43].
Hit Selection and Validation: Select the top 100-500 compounds based on VSH scores and chemical diversity. Procure compounds for experimental validation using binding affinity assays (e.g., SPR, FRET) and cell-based infectivity models relevant to the parasitic zoonosis [43].
Table 1: Benchmarking Performance of RosettaVS on CASF-2016 Dataset
| Performance Metric | RosettaGenFF-VS | Second-Best Method | Performance Improvement |
|---|---|---|---|
| Docking Power (Pose Prediction) | Top-performing | Other physics-based methods | Superior binding funnel efficiency [43] |
| Screening Power (EF1%) | 16.72 | 11.9 | ~40% enhancement in early enrichment [43] |
| Success Rate (Top 1%) | Highest recorded | All comparative methods | Best identification of top binders [43] |
Table 2: Essential Research Reagents for Virtual Screening
| Reagent / Resource | Function / Application | Specifications / Examples |
|---|---|---|
| RosettaVS Software | Open-source virtual screening platform | Includes VSX and VSH docking modes; compatible with HPC clusters [43] |
| Chemical Compound Libraries | Source of candidate molecules for screening | ZINC, ChEMBL, Enamine REAL; multi-billion compound capacity [43] |
| High-Performance Computing (HPC) | Computational resource for docking calculations | 3000 CPUs + GPUs; enables screening in <7 days [43] |
| Target Protein Structures | Molecular target for docking | PDB-derived or homology models; parasitic zoonoses targets (e.g., trypanothione reductase) |
PK/PD modeling is a mathematical approach that integrates pharmacokinetics (what the body does to the drug) and pharmacodynamics (what the drug does to the body) to describe the time course of drug effects [45] [46] [47]. For wildlife parasitic zoonoses, these models are invaluable for optimizing dosing regimens across multiple speciesâhumans, domestic animals, and wildlifeâin alignment with One Health principles.
Mechanism-based PK/PD modeling separates drug-specific, delivery system-specific, and physiological system-specific parameters, enabling a more predictive understanding of a drug's in vivo behavior [45] [47]. The basic framework involves:
The diagram below illustrates the structural relationships between core PK/PD models used in drug development for complex diseases:
Fundamental PK Models:
One-Compartment Model with First-Order Absorption:
One-Compartment Model with Zero-Order Absorption:
Fundamental PD Models:
Direct Effect Models:
E = E0 + (Emax · C^γ) / (EC50^γ + C^γ) [46]Indirect Response Models:
Protocol Details:
Study Design: Conduct in vivo studies in relevant animal models (e.g., rodent models of parasitic infection). Administer the drug via the intended route (IV, oral, etc.) at multiple dose levels. Collect serial blood samples at predetermined time points for PK analysis. Simultaneously, record PD measurements (e.g., parasite burden, biomarker levels) over time [45] [47].
Bioanalytical Assays: Quantify drug concentrations in plasma and tissues using validated methods (e.g., LC-MS/MS). Measure relevant PD biomarkers specific to the parasitic zoonosis (e.g., serological markers, molecular parasite detection) [45].
PK Model Development: Fit concentration-time data to appropriate compartmental models (1, 2, or 3 compartments) using non-linear mixed-effects modeling software (e.g., NONMEM, Monolix). Estimate parameters: clearance (CL), volume of distribution (V), absorption rate (ka) [45] [47].
PD Model Development: Correlate drug concentration (or concentration in a hypothetical effect compartment) with the observed effect. Test different PD models (Direct, Indirect Response) to identify the best structure that describes the data [46] [47].
Model Validation: Validate the final PK/PD model using diagnostic plots (observed vs. predicted concentrations/effects), visual predictive checks, and bootstrap analysis. Use the model to simulate different dosing scenarios to identify an optimal regimen for efficacy studies in target species (human and animal) [45].
Table 3: Application of PK/PD Modeling in Drug Delivery Systems for One Health
| Application Domain | PK/PD Contribution | One Health Relevance |
|---|---|---|
| Extended-Release Formulations | Predicts drug release profile and optimizes formulation parameters | Reduces dosing frequency; improves compliance in human and animal populations [45] [47] |
| Liposomal Drugs & Nanoparticles | Quantifies carrier clearance, drug release rate, and target site accumulation | Enhances drug delivery to specific tissues; reduces off-target toxicity in wildlife [45] |
| Modified Proteins & Antibody-Drug Conjugates | Models complex disposition and target-mediated drug disposition | Optimizes biologics for parasitic targets; informs interspecies dosing [45] |
| Wildlife Dosage Optimization | Extrapolates PK/PD relationships from lab animals to wildlife species | Enables effective dosing in wildlife reservoirs to break transmission cycles |
Table 4: Essential Research Reagents for PK/PD Modeling
| Reagent / Resource | Function / Application | Specifications / Examples |
|---|---|---|
| Animal Disease Models | In vivo PK/PD data generation | Rodent and non-rodent models of parasitic infection (e.g., mice, hamsters) |
| Bioanalytical Instrumentation | Drug and biomarker quantification | LC-MS/MS systems; validated analytical methods for drug and metabolites |
| Modeling & Simulation Software | PK/PD model development and parameter estimation | NONMEM, Monolix, R, Phoenix NLME; population PK/PD analysis capabilities |
| Physiological Fluids & Tissues | Matrices for drug concentration measurement | Plasma, serum, tissue homogenates from target organs |
Drug repurposing offers a cost-effective strategy for identifying new therapeutic uses for existing drugs, significantly reducing the time and resources required compared to de novo drug development [14] [42]. This approach is particularly compelling for neglected wildlife parasitic zoonoses, where economic incentives for new drug development are limited.
The economic case for repurposing is strong: de novo drug development often exceeds 15 years and costs billions of dollars, whereas repurposing can slash development timelines and costs by 50% or more [14] [42]. The workflow integrates computational and experimental approaches:
Notable Repurposing Successes:
AI-Accelerated Repurposing: Artificial intelligence and machine learning algorithms can systematically analyze large-scale datasets (e.g., genomic, proteomic, clinical data) to identify novel drug-disease associations that would be difficult to detect through traditional methods [14] [42]. For example, network analysis of host-parasite protein interactions can reveal unexpected drug targets and corresponding inhibitors from existing drug libraries.
The true power of computational biology in addressing wildlife parasitic zoonoses emerges when virtual screening, PK/PD modeling, and repurposing strategies are integrated within a cohesive One Health framework. This integrated approach considers the complex ecological interactions between humans, animals, and environments that characterize zoonotic disease transmission [41] [30].
The "zoonotic web" concept provides a network representation of the complex relationships between zoonotic agents, their hosts, vectors, and environmental sources [30]. Analyzing this web through network metrics identifies critical intervention points for disrupting transmission cycles. Key insights from such analyses include:
While computational methods offer transformative potential for zoonoses drug discovery, significant challenges remain in their implementation within One Health strategies:
Future progress depends on enhanced data sharing across human, animal, and environmental health sectors, development of adaptable modeling frameworks that account for interspecies differences, and regulatory innovation to accommodate the unique challenges of One Health therapeutic development [41] [30].
Computational biology provides an indispensable toolkit for advancing drug discovery against wildlife parasitic zoonoses within a One Health framework. Virtual screening enables rapid identification of hit compounds from immense chemical libraries; PK/PD modeling optimizes dosing regimens across multiple species; and drug repurposing offers a cost-effective strategy to expand the therapeutic arsenal. By integrating these approaches and acknowledging the interconnected nature of health across human, animal, and environmental domains, researchers can develop more effective, economically viable interventions against these neglected diseases. As climate change and ecological disruption increase human-wildlife interactions, these computational strategies will become increasingly vital for global health security, enabling proactive rather than reactive responses to emerging zoonotic threats.
The One Health approach fundamentally acknowledges that human health is intrinsically linked to animal health and the condition of the shared environment [7]. This integrated framework is critical for combating zoonotic diseases, which are infections naturally transmissible between vertebrates and humans, and which account for approximately 60% of all known human infectious diseases and up to 75% of emerging pathogens [4] [5]. The persistent threat of zoonoses, from well-established pathogens like Brucella and rabies to emerging threats such as SARS-CoV-2 and avian influenza, demands innovative therapeutic strategies that are effective across species boundaries [7] [48]. This whitepaper explores novel therapeutic platformsâencompassing natural immunomodulatory compounds, advanced vaccine adjuvants, and cross-species vaccine developmentâwithin the context of a unified One Health strategy, providing technical guidance for researchers and drug development professionals focused on mitigating the global impact of parasitic and other wildlife zoonoses.
Natural products, derived from a diverse range of plants, fungi, and marine organisms, represent a rich source of immunomodulatory compounds with significant potential for therapeutic and prophylactic applications against zoonotic infections.
Table 1: Characteristics of Selected Natural Immunopotentiators
| Source | Compound Class | Example Compounds | Reported Immunomodulatory Activities | Key Findings from Preclinical Studies |
|---|---|---|---|---|
| Plants | Saponins | QS-21, Ginsenosides (e.g., Rb1), Tomatine | Stimulates Th1 responses and T-cell activation; induces balanced Th1/Th2 response (Ginsenosides); upregulates IFN-γ [49]. | Quil A and QS-21 show hemolytic effects and toxicity in trials; Ginsenoside Rb1 enhanced antibody response in cattle; Tomatine adjuvant was safe in mice and effective in malaria and tularemia vaccines [49]. |
| Plants | Polysaccharides | Inulin (Gamma, Delta/Advax) | Potent humoral and cellular immune response; induces both Th1 (IgG2a, IL-2, IFN-γ) and Th2 (IgG1, IgA, IL-5, IL-6) responses [49]. | Advax (delta inulin) tested against influenza, SARS, HIV, Listeria, and hepatitis B; shows little to no side effects and greater temperature stability than gamma inulin [49]. |
| Fungi | β-Glucans | β-1,3-D-glucans, β-1,6-D-glucans | Stimulates innate immune cells via dectin-1 receptor binding; stimulates proinflammatory cytokines (TNF-α, IL-1β, IL-6) [49]. | Water-soluble, high-molecular-weight β-glucans show better activity; acid-resistant, ideal for oral administration; extracts from Ganoderma lucidum increased IFN-γ in human PBMCs [49]. |
| Marine/Insects | Glycolipids/Peptides | α-Galactosylceramide, Chitosan, Bee Venom Peptides | Establishes adjuvant activity; chitosan commonly produced from shrimp chitin [49]. | α-Galactosylceramide originally obtained from a marine sponge [49]. |
Protocol 1: In Vitro Immunostimulation Assay for Natural Compounds
Protocol 2: Adjuvant Efficacy Testing in a Murine Model
Diagram 1: Immunomodulation by natural compounds. Natural compounds like saponins and β-glucans engage pattern recognition receptors on innate immune cells, triggering cytokine release that orchestrates a balanced Th1/Th2 adaptive immune response, leading to enhanced antibody production and potential cross-species protection against zoonoses.
A core principle of One Health vaccinology is the potential development of single vaccine formulations effective across multiple susceptible species, from wildlife and livestock to humans. A major challenge is that adjuvants suitable for one species can be ineffective or unsafe in another [48].
Table 2: Adjuvants in Licensed Vaccines and One Health Suitability
| Adjuvant Type | Mode of Action | Representative Examples | Key Advantages | Disadvantages / Species-Specific Concerns | One Health Suitability |
|---|---|---|---|---|---|
| Mineral Salts | Retain antigen at injection site; induce Th2 responses. | Alhydrogel, Adjuphos | Good safety profile in humans; low cost; strong humoral response. | Poor Th1 induction; high reactogenicity in felines (can cause injection site sarcomas) [48]. | Low: Unsuitable for cats. |
| Oil Emulsions | Form antigen depot; induce inflammatory cytokines. | MF59, AS03, Emulsigen-D | Strong Th2 immunity; low cost; long-term immunity. | Mineral oil emulsions (e.g., Freund's) are too reactogenic for humans; can cause granulomas [48]. | Variable: Squalene-based (MF59) show promise; mineral oil types not for humans. |
| Immune-Stimulating Complexes (ISCOM) | Activate inflammasome; induce T cell & humoral responses. | Quil A, QS-21, ISCOM, VetSap | Strong humoral and cellular immune response. | Potential toxicity; hemolysis; granulomas; local inflammatory reactions [49] [48]. | Moderate: Toxicity concerns require careful dosing. |
| Polysaccharides | Stimulate cellular & humoral immunity via DC-SIGN. | Delta inulin (Advax) | Does not require antigen adsorption; can be combined; good safety profile. | None major identified in research to date [48]. | High: Safe and effective across species. |
| Combination Adjuvants | Combines immune stimulators with delivery systems. | Advax-CpG55.2, Alum + MPLA | Enhances both Th1 and Th2 immunity. | See individual component data. | High: Broad species activity and safety. |
Based on current evidence, two adjuvant platforms stand out for their broad species compatibility:
Protocol 3: Cross-Species Adjuvant Efficacy and Safety Testing
Diagram 2: One Health vaccine development workflow. This integrated pathway outlines the process from pathogen identification through to coordinated deployment, emphasizing parallel efficacy and safety testing in multiple animal species and humans to ensure broad applicability.
Effective implementation of One Health strategies requires robust quantitative tools to prioritize threats and evaluate the performance of surveillance systems.
Conjoint Analysis (CA) is a quantitative market research technique adapted to prioritize zoonotic diseases based on multiple criteria without the bias of disease names. It involves presenting stakeholders with choice tasks containing different combinations of disease characteristics (e.g., mortality, transmissibility, economic impact) and analyzing their preferences to derive weighted scores for each criterion [4].
Assessment tools like the one developed by the Africa CDC provide a structured way to evaluate the operational capacity of One Health platforms, particularly in resource-limited settings.
Table 3: Key Research Reagent Solutions for One Health Therapeutic Development
| Reagent / Material | Function / Application | Specific Examples & Notes |
|---|---|---|
| Pattern Recognition Receptor Agonists | To stimulate innate immune pathways in vitro and in vivo for immunopotentiator studies. | TLR ligands (e.g., Poly I:C, CpG ODN), Dectin-1 agonists (e.g., β-Glucans from S. cerevisiae). |
| Species-Specific Immunoassays | To quantify immune responses (antibodies, cytokines) in different target species. | ELISA kits for bovine IgG, feline IFN-γ, etc.; Multiplex bead arrays validated for multiple species. |
| Cell Lines and Primary Cells | For in vitro screening of compound toxicity and immunomodulatory activity. | THP-1 (human monocyte), RAW 264.7 (mouse macrophage), primary PBMCs/DCs from target species (e.g., chicken, cow). |
| Model Antigens | To standardize adjuvant testing and immunization protocols. | Ovalbumin (OVA), Keyhole Limpet Hemocyanin (KLH). |
| Reference Adjuvants | As positive and negative controls in vaccine formulation studies. | Alum (for Th2 bias), Quil A/QS-21 (for Th1/antibody response), Squalene emulsions (e.g., MF59). |
| One Health Assessment Tools | To quantitatively evaluate platform performance and disease priority. | Africa CDC evaluation tool, OH-EpiCap, Conjoint Analysis survey instruments [4] [5]. |
| Kadsurenin A | Kadsurenin A | High-purity Kadsurenin A isolated from Piper kadsura. For phytochemical and pharmacological research use only (RUO). Not for human or veterinary use. |
| Ceplignan | Ceplignan | Ceplignan is a [compound class] for life science research. Explore its applications in [research area]. For Research Use Only. Not for human use. |
The development of novel therapeutic platforms against wildlife parasitic zoonoses is vastly strengthened by adopting a One Health perspective. The integration of natural immunomodulatory compounds like saponins and β-glucans, combined with rationally selected cross-species vaccine adjuvants such as Advax-CpG55.2 or squalene emulsions, provides a powerful, synergistic strategy for preemptive and reactive disease management. Future efforts must focus on overcoming the significant implementation barriers identified in field evaluations, including inadequate funding, training, and material resources, particularly in hotspot regions. By leveraging quantitative prioritization tools like Conjoint Analysis and robust platform performance metrics, the global research community can strategically direct resources toward the most pressing threats and ensure that scientific innovation translates into tangible, cross-species health security.
The increasing burden of emerging infectious diseases worldwide, approximately 60-75% of which are zoonotic in origin, confronts researchers with complex challenges that cannot be adequately addressed through singular disciplinary lenses [4] [50]. The Transdisciplinary and social-ecological health frameworks have emerged as essential approaches for understanding the functional prerequisites of health, sustainable vitality, and wellbeing across species and ecosystems [51]. These frameworks recognize that health interconnects species across the planet and offer more effective ways to tackle complex real-world challenges that defy traditional disciplinary boundaries [51] [52]. In the specific context of wildlife parasitic zoonoses researchâincluding pathogens such as Trypanosoma cruzi, Echinococcus spp., Trichinella, and Toxoplasmaâtransdisciplinary approaches enable researchers to move beyond simplistic host-pathogen interaction models toward a more comprehensive understanding of the social-ecological systems in which these diseases persist and emerge [30] [53]. This technical guide provides a comprehensive framework for implementing transdisciplinary approaches that integrate epidemiology, ecology, and social science methodologies within the broader context of One Health research on wildlife parasitic zoonoses.
The conceptual foundation for transdisciplinary research in zoonoses has evolved significantly over recent decades. Integrative concepts and practices of health in transdisciplinary social ecology have emerged to contend with linkages between the subjects, attributes, determinants, and fields of health in humans, other species, and their shared ecological systems [52]. These concepts include One Health, EcoHealth, ecosystem health, and planetary health, which together transform human-centered definitions of health toward more inclusive frameworks [52]. Despite their varied terminology and historical development, these integrative concepts share a common recognition that the delineation between social systems and ecosystems is artificial and arbitrary, necessitating approaches that explicitly engage with their interconnectedness [50] [52].
A critical theoretical advancement has been the conceptualization of the zoonotic web (akin to a "food web"), which represents a network of zoonotic actors at human-animal-environment interfaces [30]. This framework extends beyond traditional host-pathogen models to include vectors, food, and environmental sources, offering a more robust foundation for understanding complex transmission dynamics of parasitic zoonoses [30]. The zoonotic web concept enables researchers to characterize the key interfaces where spillover events occur, particularly at human-cattle and human-food interfaces, which network analysis has identified as having an increased probability of zoonotic spillover [30].
The social-ecological systems framework provides an essential theoretical foundation for transdisciplinary research on parasitic zoonoses. This framework recognizes humans as both part of nature and fundamentally conditioned by social activity, creating coupled human-natural systems [50]. Within these systems, parasitic zoonoses exist within nested hierarchies operating at multiple levelsâmolecular, organismal, communal, national, and globalârequiring research approaches that can address this complexity [50].
Research into parasite zoonoses and wildlife within this framework demonstrates that human activity is central to zoonotic transmission, with spillover events occurring not only from wildlife to humans and domestic animals but also from domestic foci of transmission to wildlife [53]. This bidirectional flow of parasites establishes novel spill-back reservoirs of potential public health and economic significance, while also threatening wildlife conservation [53]. The social-ecological systems framework thus necessitates consideration of the full spectrum of transmission pathways and their societal drivers.
Table 1: Key Theoretical Frameworks for Transdisciplinary Zoonoses Research
| Framework | Core Principles | Application to Wildlife Parasitic Zoonoses |
|---|---|---|
| One Health | Integrates human, animal, and environmental health | Examines interfaces where parasite transmission occurs between wildlife, domestic animals, and humans |
| EcoHealth | Emphasizes ecological determinants of health | Investigates how ecosystem changes influence parasite life cycles and transmission dynamics |
| Social-Ecological Systems | Views social and ecological systems as coupled, complex adaptive systems | Analyzes how societal and ecological factors interact to drive zoonotic disease emergence |
| Zoonotic Web | Network-based representation of zoonotic actors and their interactions | Maps complex relationships between zoonotic agents, hosts, vectors, food, and environment |
Implementing transdisciplinary research requires methodological frameworks that facilitate genuine integration of epidemiological, ecological, and social science approaches. The ecosystem approaches to health provide valuable precedents for research methods that explicitly engage with the ecological and social systems within which health is created and challenged [50]. These approaches emphasize several key design principles:
A exemplar of this approach can be found in the Austrian case study that compiled 47 years of data on zoonotic interactions to create a comprehensive zoonotic web [30]. This research employed systematic literature searches, network analysis, and temporal trend analysis to identify key interfaces and communities of zoonotic agent sharing, demonstrating how transdisciplinary approaches can optimize surveillance strategies tailored to regional contexts [30].
Advanced quantitative methods facilitate the integration of diverse data types across disciplinary boundaries. Conjoint Analysis (CA) represents a particularly promising approach for prioritizing zoonotic diseases based on multiple criteria [4]. This method, adapted from market research, treats diseases as "products" described by a set of characteristics and determines their relative priority through analysis of stakeholder preferences [4]. The methodology involves:
Network analysis provides another powerful quantitative approach for transdisciplinary research. The Austrian zoonotic web study treated zoonotic interactions as a bipartite network and transformed it into a one-mode projection representing the network of zoonotic agent sharing among zoonotic sources [30]. This approach weighted relationships between zoonotic sources by the number of zoonotic agents they shared, enabling identification of the most influential zoonotic sources and communities of zoonotic agent sharing [30].
Table 2: Quantitative Methods for Transdisciplinary Zoonoses Research
| Method | Application | Data Requirements | Analytical Outputs |
|---|---|---|---|
| Conjoint Analysis | Disease prioritization based on multiple criteria | Stakeholder preference data on disease characteristics | Weighted scores for disease criteria; ranked list of priority diseases |
| Network Analysis | Mapping complex relationships in zoonotic webs | Data on interactions between hosts, pathogens, vectors, and environments | Network metrics identifying key nodes, interfaces, and communities |
| Social-Ecological Systems Modeling | Simulating disease dynamics in coupled systems | Interdisciplinary data on social, ecological, and epidemiological variables | Predictive models of disease emergence under different scenarios |
| Spatial Analysis | Identifying hotspots of disease transmission | Georeferenced data on hosts, vectors, human populations, and land use | Risk maps guiding targeted surveillance and intervention |
Effective transdisciplinary research requires robust protocols for integrating diverse data types. The following workflow provides a framework for data integration in wildlife parasitic zoonoses research:
Data Integration Workflow for Transdisciplinary Research
The Austrian zoonotic web study exemplifies this approach, creating a comprehensive dataset with 2128 rows and 48 data fields spanning 47 years of research [30]. Each entry represented one investigated zoonotic agent along with results from animal hosts, vectors, and environmental or food matrices, enabling both temporal trend analysis and cross-sectional network analysis [30].
Field implementation of transdisciplinary approaches requires surveillance strategies that simultaneously capture epidemiological, ecological, and social data. The Austrian case study demonstrated a 17.8-fold increase in publications on zoonoses between the first (1975-1997) and second half (1998-2022) of the study period, with particular attention to zoonotic bacteria, viruses, and eukaryotes [30]. This research identified 227 unique zoonotic agents investigated in Austria, with ten genera (Salmonella, Escherichia, Listeria, Echinococcus, Orthoflavivirus, Brucella, Toxoplasma, Campylobacter, Trichinella, and Leptospira) collectively accounting for 41% of the selected literature [30].
A critical finding from this research was that most zoonotic agents (76.9%) were studied in wildlife hosts, which accounted for 221 animal species investigated [30]. This highlights the importance of wildlife surveillance within transdisciplinary approaches, though the authors noted that environmental aspects (including environmental media, plant-based food, and vectors) were not considered in studies on zoonotic diseases in Austria until 1997 [30]. Subsequent research demonstrated a gradual increase in scientific attention to these environmental components, primarily driven by a rise in investigations on vectors [30].
Transdisciplinary approaches reveal the complex dynamics of spillover events for parasitic zoonoses. Research on parasite zoonoses and wildlife demonstrates that spillover occurs not only from wildlife to humans and domestic animals but also in the reverse direction, from domestic foci of transmission to wildlife [53]. This bidirectional flow establishes novel spill-back reservoirs of potential public health and economic significance, while also threatening wildlife conservation [53].
The Austrian zoonotic web analysis confirmed the increased probability of zoonotic spillover at human-cattle and human-food interfaces through analysis of One Health 3-cliques (triangular sets of nodes representing human, animal, and environment) [30]. Furthermore, the study characterized six communities of zoonotic agent sharing, whose assembly patterns appeared to be driven by highly connected infectious agents in the zoonotic web, proximity to human, and anthropogenic activities [30]. This community structure provides valuable insights for targeting surveillance and intervention strategies.
Anthropogenic Drivers of Zoonotic Spillover Events
Transdisciplinary approaches necessitate meaningful engagement with communities and stakeholders beyond academia. The All Hands on Deck ethos emphasizes cooperation and the melding of ideas from all walks of science and life [50]. This approach recognizes that effective responses to emerging infectious diseases require integration of a wide variety of disciplinary knowledge, as well as the inclusion of knowledge from outside of academia [50].
A key methodology for facilitating this integration is the development of communities of practice where knowledge is generated, shared, processed, translated, negotiated, and used [52]. These communities provide the social structures necessary for transdisciplinary collaboration, enabling researchers to conceive the challenges and opportunities of integration collectively [52]. Research on integrative health concepts indicates that while contexts, goals, and rationales vary, these concepts essentially arise from shared interests in living systems [52].
Implementing transdisciplinary research requires specialized analytical tools capable of integrating and visualizing complex, multidimensional data. The following tools represent essential resources for researchers combining epidemiology, ecology, and social science:
Table 3: Essential Analytical Tools for Transdisciplinary Zoonoses Research
| Tool/Platform | Primary Function | Application in Transdisciplinary Research |
|---|---|---|
| Network Analysis Software | Analysis of complex relationships between entities | Mapping zoonotic webs identifying key interfaces and transmission pathways |
| Conjoint Analysis Platforms | Quantitative analysis of multi-criteria decision making | Prioritizing zoonotic diseases based on diverse stakeholder values |
| Geographic Information Systems | Spatial analysis and visualization | Identifying hotspots of transmission risk at human-animal-environment interfaces |
| Google Visualization API | Creation of interactive charts and data visualizations | Communicating complex transdisciplinary findings to diverse audiences |
The Google Visualization API provides particularly valuable capabilities for creating interactive charts and data visualizations based on pure HTML5/SVG technology [54] [55]. This API enables researchers to develop DataTable objects that represent two-dimensional, mutable tables of values, with each column assigned a specific data type and optional properties including an ID, label, and pattern string [55]. These visualization capabilities are essential for communicating complex transdisciplinary findings to diverse stakeholder groups.
Field research on wildlife parasitic zoonoses requires specialized reagents and materials for sample collection, preservation, and analysis. The following table details essential research reagents and their applications in transdisciplinary studies:
Table 4: Essential Research Reagents for Wildlife Parasitic Zoonoses Studies
| Reagent/Material | Specifications | Application in Transdisciplinary Research |
|---|---|---|
| Sample Collection Kits | Standardized kits for diverse sample types | Enable comparable sampling across host species, vectors, and environmental matrices |
| Molecular Diagnostic Assays | PCR, qPCR, and sequencing reagents | Pathogen detection and characterization across human, animal, and environmental samples |
| Serological Testing Kits | ELISA, Western blot, and other immunoassays | Detection of exposure to zoonotic parasites in human and animal populations |
| Environmental DNA Extraction Kits | Specialized reagents for low-concentration samples | Pathogen detection in soil, water, and other environmental media |
| Geolocation Equipment | GPS units with specified accuracy | Spatial mapping of sample locations for integration with ecological and social data |
| Structured Interview Protocols | Validated survey instruments | Collection of social science data on human behaviors, perceptions, and exposures |
This technical guide has outlined the theoretical foundations, methodological approaches, and practical implementations of transdisciplinary research combining epidemiology, ecology, and social science in the study of wildlife parasitic zoonoses. The frameworks and methods presented here provide researchers with essential tools for addressing the complex challenges posed by emerging and endemic parasitic diseases at the human-animal-environment interface.
The continuing evolution of integrative concepts and practices of health in transdisciplinary social ecology points toward an increasingly sophisticated understanding of the linkages between human, animal, and ecosystem health [52]. There is an urgent need for better, coherent, and more deeply integrative health concepts, approaches, and practices to foster the well-being of humans, other animals, and ecosystems [52]. Consideration of these concepts and practices has both methodological and political importance, as it transforms thinking and action on both society and nature, enriching science and practice while expanding their scope and linkages [52].
Future advances in this field will depend on continued development of transdisciplinary health approaches that properly address the multiple facets of health and achieve their appropriate integration for the socio-ecological systems at stake [52]. As researchers, scientists, and drug development professionals implement these approaches, they contribute not only to the control of specific parasitic zoonoses but to the broader development of knowledge systems capable of addressing the complex health challenges of the Anthropocene.
The One Health approach recognizes that the health of people is intimately connected to the health of animals and our shared environment [2]. This interconnectedness is particularly critical when addressing wildlife parasitic zoonoses, where pathogens circulate among animal reservoirs and can spill over into human populations. Effective management of these health threats relies fundamentally on robust diagnostic capabilities, yet significant technical barriers impede accurate detection and surveillance, especially in resource-limited settings [56] [57]. These limitations directly impact early outbreak detection, effective response strategies, and the overall understanding of disease dynamics at the critical human-animal-environment interface.
The challenges are multifaceted, stemming from both the intrinsic complexities of wildlife hosts and the practical constraints of resource-poor environments. Wildlife species present unique diagnostic hurdles, including unknown pathogen diversity, diverse and often inaccessible host species, and a poor understanding of infection dynamics in wild populations [58]. Simultaneously, laboratories and field settings in many regions face severe limitations in financial resources, technical expertise, infrastructure, and access to advanced diagnostic technologies [59] [60]. This article examines these technical barriers within the context of a broader thesis on One Health approaches to wildlife parasitic zoonoses research, providing a detailed analysis of current limitations and potential pathways toward more equitable and effective diagnostic capabilities.
Investigating pathogens in wildlife hosts presents a unique set of challenges that distinguish it from diagnostic work in human or domestic animal medicine. These impediments are largely related to the zoological, behavioral, and ecological characteristics of wildlife populations and to limited access to investigation materials [58].
Host Diversity and Unknown Pathogen Profiles: The immense biodiversity of wildlife hosts means that pathogens exist within a vast and often uncharacterized ecological landscape. Unlike humans or livestock, for which expected pathogen profiles are well-documented, wildlife may harbor novel, emerging, or unexpected infectious agents. This complexity is compounded by the fact that properties conferring pathogenicity depend as much on the host as they do on the microorganism and may be influenced by multiple factors such as environmental stress, pollutants, and other microorganisms [58].
Accessibility and Sampling Limitations: Free-ranging wildlife is inherently difficult to access, leading to substantial sampling biases. Many surveillance systems rely on convenience sampling (e.g., hunter-harvested animals, roadkill, or animals showing clinical signs), which does not represent the true health status of populations [58]. Capturing healthy animals for sampling is logistically complex, expensive, and may alter animal behavior or physiology, thereby affecting diagnostic results.
Defining "Health" in Wildlife Populations: Applying standard medical definitions of health to wildlife is problematic. Health has been redefined as "the ability to adapt and to self-manage" â an organism is healthy if it capable of maintaining physiological homeostasis through changing circumstances [58]. Measuring this capacity requires tools for assessing an individual's ability to cope and adapt, which are often lacking for wildlife species. Furthermore, reservoir hosts may carry pathogens asymptomatically, making disease detection based solely on clinical signs ineffective [56] [58].
Most diagnostic tests are developed and validated for human medicine or domestic animals, creating significant limitations when applied to wildlife species:
Lack of Validated Assays: Very few diagnostic tests are specifically validated for wildlife species, leading to potential issues with sensitivity, specificity, and accuracy [58]. Commercial assays may produce false positives or negatives due to cross-reactions with wildlife-specific pathogens or immune factors.
Unknown Effects of Stress and Physiology: The stress of capture and handling can alter wildlife physiology in ways that affect diagnostic parameters. These effects are poorly quantified for most species, complicating result interpretation [58].
Sample Quality and Degradation: Field conditions often compromise sample quality through delayed processing, improper storage, or contamination. These factors are particularly problematic for molecular diagnostics, where sample degradation can profoundly impact results [58].
Table 1: Key Challenges in Wildlife Health Investigations and Their Implications
| Challenge | Specific Limitations | Impact on Diagnostic Accuracy |
|---|---|---|
| Host Diversity | Unknown pathogen profiles; uncharacterized immune responses | Inability to detect novel pathogens; false negatives |
| Sampling Biases | Over-representation of clinically ill or easily captured animals | Skewed prevalence estimates; missed subclinical infections |
| Diagnostic Validation | Tests optimized for domestic species, not wildlife | Unknown test performance characteristics; potential cross-reactivity |
| Sample Degradation | Delayed processing in field conditions | Nucleic acid degradation; reduced viability of cultures |
| Reference Intervals | Lack of established normal physiological parameters | Difficulty distinguishing health from disease states |
Resource-limited settings face a distinct set of challenges that compound the inherent difficulties of wildlife diagnostics. These constraints affect every stage of the diagnostic process, from sample collection to result interpretation and reporting.
The core infrastructure limitations in resource-limited settings create fundamental barriers to effective diagnostic services for wildlife zoonoses:
Limited Laboratory Capacity: Many regions lack basic laboratory equipment, reliable electricity, temperature-controlled storage, and internet connectivity essential for modern diagnostic work [60]. This limitation is particularly acute for molecular methods that require precise temperature control and uninterrupted power supply.
Financial Constraints: High costs of commercial diagnostic kits, reagents, and equipment maintenance place advanced technologies beyond reach for many laboratories [59] [60]. This financial limitation often forces reliance on less accurate but more affordable methods, compromising surveillance quality.
Supply Chain Issues: Unreliable supply chains for critical reagents, consumables, and equipment parts can halt diagnostic operations for extended periods. This problem is especially pronounced in remote areas where wildlife zoonoses surveillance is most needed [60].
The success of diagnostic systems depends heavily on human expertise, which is often limited in resource-constrained settings:
Technical Expertise Gaps: Complex diagnostic techniques require specialized training that may be unavailable in many regions [61] [60]. Without adequate training and quality assurance programs, even well-equipped laboratories may produce unreliable results.
Workforce Shortages: Many facilities operate with insufficient staff, leading to workload pressures that compromise attention to detail and adherence to standardized protocols [60]. High staff turnover further exacerbates these challenges.
Limited Access to Knowledge Resources: Restricted access to current scientific literature, technical guidelines, and expert consultation isolates professionals from advances in the field [60].
Different diagnostic methodologies present unique challenges in resource-limited settings:
Molecular Diagnostics (e.g., PCR): While PCR and related methods offer high sensitivity and specificity, they require sophisticated equipment, trained personnel, and reliable reagent supply chains [61]. Real-time PCR, despite its advantages in speed and contamination reduction, requires even more specialized equipment and expensive reagents [61].
Antigen Detection Rapid Diagnostic Tests (Ag-RDTs): These tests offer practical advantages as they are inexpensive, faster, and easy to use [59]. However, this comes at the cost of reduced sensitivity compared to molecular methods. A meta-analysis of COVID-19 Ag-RDTs in low- and middle-income countries demonstrated a pooled sensitivity of 78.2% and specificity of 99.5% [59], approaching but not meeting the minimum performance requirements for outbreak detection.
Serological Assays: While generally more accessible than molecular methods, serological tests require validation for local wildlife species and may not distinguish between current and past infections. Proper storage of reagents is also a challenge without consistent refrigeration [58].
Table 2: Comparison of Diagnostic Method Limitations in Resource-Limited Settings
| Method | Key Advantages | Key Limitations in Resource-Limited Settings | Infrastructure Requirements |
|---|---|---|---|
| Conventional PCR | High sensitivity and specificity; broad pathogen detection | Contamination risk; requires specialized equipment; expensive reagents | Thermocycler, electrophoresis equipment, reliable power |
| Real-time PCR | Rapid results; quantitative; reduced contamination risk | Higher equipment costs; technical expertise needed; complex troubleshooting | Real-time PCR instrument, computer, stable power supply |
| Antigen RDTs | Low cost; rapid results; minimal training needed | Lower sensitivity; limited multiplexing capability; quality variability | Minimal; possible reading device |
| Serology | Detects immune response; useful for surveillance | Cannot detect active infection; requires species-specific validation | ELISA readers, washers (for some formats) |
| Culture | Gold standard for viability; allows further characterization | Prolonged time-to-result; requires viable organisms; biosafety concerns | Incubators, biosafety cabinets, sterile supplies |
A effective One Health approach to diagnosing wildlife parasitic zoonoses requires integrated surveillance systems that simultaneously address human, animal, and environmental health. However, significant technical and operational challenges impede the implementation of such integrated systems.
Data Silos and Interoperability: Human, animal, and environmental health data are typically collected by different sectors using incompatible systems and standards [57] [62]. This lack of interoperability prevents the data integration necessary for understanding transmission dynamics across species and ecosystems.
Diagnostic Standardization Challenges: Different sectors often use different diagnostic methods, making direct comparison of results difficult [58] [57]. Harmonizing diagnostic approaches across wildlife, domestic animal, and human health sectors remains a significant challenge.
Limited Diagnostic Capacity at Human-Animal-Environment Interfaces: Critical interfaces where transmission occurs (e.g., wildlife-livestock-human contact points) often have the least diagnostic capacity [57]. This creates surveillance blind spots exactly where early detection is most critical.
The following diagram illustrates the complex workflow and multiple potential failure points in integrated zoonotic disease surveillance:
Integrated Zoonoses Surveillance Workflow and Barriers
A critical technical barrier in both wildlife hosts and resource-limited settings is the validation of diagnostic tests. The process of test validation presents particular challenges:
Gold Standard Limitations: For many emerging wildlife zoonoses, no true gold standard test exists, making validation problematic [58]. This is particularly true for novel pathogens where the only available comparator may be another imperfect test.
Species-Specific Validation Requirements: Tests validated for one wildlife species may perform differently in others due to genetic variations, immune responses, or pathogen strains [58]. Comprehensive multi-species validation is rarely feasible due to cost and sample availability constraints.
Environmental Impacts on Test Performance: Field conditions in resource-limited settings, including extreme temperatures, humidity, and dust, can affect test reagents and equipment in ways not encountered in controlled laboratory environments [59] [60].
The relationship between cycle threshold (Ct) values and test sensitivity illustrates one key diagnostic challenge. While RT-PCR tests generally show an inverse relationship between Ct values and antigen test sensitivity (lower Ct values indicate higher viral loads and better detection), this relationship is not always consistent, particularly with wildlife samples where viral dynamics may differ [59].
Despite these significant challenges, technological innovations and adapted methodologies offer promising pathways to overcome diagnostic barriers in resource-limited settings and wildlife hosts.
Syndromic Surveillance and Triangulation Approaches: Given the limitations of individual diagnostic tests, combining multiple data sources through triangulation enhances detection capability [58]. This includes integrating clinical observations, pathological findings, and multiple diagnostic test results to build a composite picture of disease status.
Digital Clinical Decision Support (CDS) Tools: These tools are increasingly valuable in supporting diagnostic decision-making where specialist expertise is limited [60]. Well-designed CDS tools can integrate patient-specific data with clinical knowledge to support evidence-based diagnostic and therapeutic decisions. For wildlife health, CDS tools show particular promise in enabling non-specialists to conduct preliminary diagnoses in remote settings [60].
Point-of-Care and Field-Based Diagnostics: Development of rugged, portable diagnostic equipment suitable for field use can help overcome infrastructure limitations [59]. Similarly, heat-stable reagents and simplified sample processing methods reduce dependence on cold chains and complex laboratory setups.
Multidisciplinary Teams and Knowledge Sharing: Successful wildlife health investigations require integrating expertise from veterinary medicine, ecology, molecular biology, and epidemiology [58] [62]. Creating frameworks for such collaboration enhances diagnostic capability.
Training and Capacity Development: Investments in developing local expertise through hands-on training, mentorship programs, and sustainable educational resources build long-term diagnostic capacity [58] [60].
Diagnostic Test Development and Local Production: Developing and validating diagnostic tests specifically for priority wildlife zoonoses in target regions addresses the limitation of tests developed for domestic species [58]. Local production of reagents and test kits can mitigate supply chain issues and reduce costs.
Table 3: Essential Research Reagents and Their Applications in Wildlife Zoonoses Investigation
| Reagent Category | Specific Examples | Primary Functions | Considerations for Resource-Limited Settings |
|---|---|---|---|
| Nucleic Acid Extraction Kits | Silica-membrane based kits, magnetic bead systems | Isolation of DNA/RNA from diverse sample types; removal of PCR inhibitors | Temperature stability; shelf life; minimal equipment requirements |
| PCR Master Mixes | Lyophilized reagents, room-temperature-stable formulations | Amplification of target pathogen sequences; contains polymerase, dNTPs, buffer | Reduced cold chain dependency; pre-mixed to minimize pipetting steps |
| Positive Controls | Synthetic genes, inactivated viral particles, plasmid constructs | Verification of assay performance; quantification standards | Non-infectious alternatives for biosafety; stability without freezing |
| Primers and Probes | Broad-range consensus primers, pathogen-specific probes | Specific detection of target sequences in conventional and real-time PCR | Stability at ambient temperatures; lyophilized formats |
| Rapid Test Components | Nitrocellulose membranes, gold-conjugated antibodies, recombinant antigens | Construction of lateral flow assays for antigen or antibody detection | Stability in high humidity; simplified manufacturing requirements |
Technical barriers to diagnosing wildlife parasitic zoonoses in resource-limited settings represent a critical vulnerability in global health security. These limitations directly impact our ability to detect emerging threats, monitor disease dynamics, and implement timely control measures. The challenges are profound, spanning from fundamental biological complexities of wildlife hosts to practical constraints of infrastructure, resources, and expertise in many regions.
However, the growing recognition of these challenges within a One Health framework offers promising pathways forward. By adopting integrated surveillance approaches, developing adapted technologies suitable for field use, building local capacity, and fostering cross-sectoral collaboration, we can progressively overcome these barriers. The development of point-of-care diagnostics, digital decision support tools, and specifically validated tests for wildlife hosts will be particularly valuable in strengthening diagnostic capabilities.
Ultimately, addressing these diagnostic limitations requires sustained investment and commitment to equitable global health security. As the boundaries between human, animal, and environmental health continue to blur in our interconnected world, strengthening our ability to detect and characterize wildlife zoonotic threats remains an essential investment in preventing future pandemics and protecting global health.
Antimicrobial resistance (AMR) represents a critical global public health threat that extends significantly into the realm of parasitic diseases. The One Health approach recognizes that the health of humans, animals, plants, and their shared environments are inextricably interconnected, and this is particularly relevant for understanding and containing the spread of drug-resistant parasites [63] [1]. Parasitic diseases, including malaria, schistosomiasis, and leishmaniasis, affect millions worldwide and are increasingly compromised by rising drug resistance [63]. The World Health Organization (WHO) estimates that in 2020 alone, there were approximately 241 million cases of malaria globally, resulting in about 627,000 deaths, with most occurring among children in sub-Saharan Africa [63]. The management of these diseases is further complicated by the fact that parasites can develop resistance to multiple drugs, rendering many available treatments ineffective [64].
The drivers of parasitic AMR are complex and multifactorial, stratified into AMR-specific drivers that directly relate to drug use and misuse across human, animal, and plant health, and AMR-sensitive drivers that facilitate the spread of resistant parasites through suboptimal water, sanitation, and hygiene (WASH) provisions, inadequate infection prevention and control, and environmental contamination [65]. Climate change further exacerbates this situation by altering the geographic range of disease vectors such as mosquitoes, thereby expanding the reach of diseases like malaria and dengue fever [63]. This whitepaper provides a comprehensive technical guide for researchers, scientists, and drug development professionals working to address drug-resistant parasites within integrated One Health frameworks.
The global burden of parasitic diseases demonstrates significant health impacts across human and animal populations. Comprehensive surveillance data is essential for understanding resistance patterns and formulating effective interventions.
Table 1: Global Burden of Selected Parasitic Diseases
| Parasitic Disease | Estimated Global Cases/Year | Estimated Annual Mortality | Primary Populations Affected | Regions of Highest Prevalence |
|---|---|---|---|---|
| Malaria | 241 million (2020) [63] | 627,000 [63] | Children under 5 [63] | Sub-Saharan Africa [63] |
| Schistosomiasis | Not specified in search results | Not specified in search results | Not specified in search results | Tropical and subtropical regions [63] |
| Leishmaniasis | Not specified in search results | Not specified in search results | Not specified in search results | Tropical and subtropical regions [63] |
| Echinococcosis | Not specified in search results | 19,300 [63] | Not specified in search results | Hyperendemic areas (livestock prevalence 20-95%) [63] |
Table 2: Antimicrobial Resistance Patterns in Zoonotic Pathogens in Southeast Asia (Representative Example)
| Pathogen | Host/Setting | Resistance Patterns | Region | Citation |
|---|---|---|---|---|
| Salmonella spp. | Chickens | Increased resistance to chloramphenicol, ciprofloxacin, tetracycline, and colistin [64] | Malaysia [64] | [64] |
| Escherichia coli | Patients with urinary tract infections | Highest resistance rate to ampicillin [64] | Malaysia [64] | [64] |
| E. coli, Aeromonas sp, Vibrio sp | Aquaculture | Multidrug-resistant patterns frequently reported [64] | Southeast Asia [64] | [64] |
A robust, multi-sectoral surveillance system is fundamental to tracking the emergence and spread of drug-resistant parasites across human, animal, and environmental interfaces. The WHO Global Antimicrobial Resistance and Use Surveillance System (GLASS) represents a critical global infrastructure for this purpose, with 135 countries, territories, and areas committed to contributing data as of December 2023 [66]. The updated GLASS dashboard launched in September 2024 provides visual representations of global and regional AMR data, though its current focus is primarily on bacterial and fungal pathogens [66]. Expanding this infrastructure to include dedicated surveillance for parasitic AMR is an essential future direction.
The following diagram illustrates an integrated One Health surveillance workflow for monitoring parasitic AMR, adaptable from existing AMR surveillance models:
Integrated One Health Surveillance Workflow for Parasitic AMR
Complementing global surveillance efforts, regional networks play a crucial role. The Southeast Asian One Health Universities Network, established in 2011, aims to build workforce capacity through education and training, equipping the next generation of professionals with skills to address interconnected health challenges [64]. Similarly, the ASEAN Coordinating Centre for Animal Health and Zoonosis facilitates cooperation among member states to speed up regional coordination for preventing and controlling zoonotic diseases [64].
Protocol: Microdilution Assay for Antiparasitic Drug Susceptibility
Protocol: PCR-Based Detection of Resistance Markers
The relationship between molecular resistance mechanisms and their functional consequences can be visualized as follows:
Molecular Mechanisms of Parasitic Drug Resistance
Table 3: Essential Research Reagents for Parasitic AMR Investigations
| Reagent/Category | Specific Examples | Research Function | Application Notes |
|---|---|---|---|
| Culture Media | RPMI-1640 (Plasmodium), Schneider's Insect Medium (Leishmania) | In vitro parasite maintenance and drug exposure studies | Requires species-specific supplementation with sera, nutrients, and growth factors [63] |
| Reference Compounds | Artemisinin, Chloroquine, Praziquantel, Miltefosine | Drug susceptibility assay controls and standardization | Source from recognized authorities (e.g., WHO, MMV) for quality assurance |
| Molecular Biology Kits | Nucleic acid extraction kits, PCR master mixes, sequencing reagents | Genetic characterization of resistance markers | Select kits validated for specific parasite matrices (blood, tissue, feces) |
| Viability Assay Kits | SYBR Green I, MTT, alamarBlue, ATP-based luminescence | Quantification of parasite growth inhibition | Optimization required for different parasite life stages and species |
| Antibodies | Species-specific monoclonal/polyclonal antibodies | Immunodetection in phenotypic assays | Useful for species identification and load quantification in mixed infections |
| Montixanthone | Montixanthone, MF:C14H10O6, MW:274.22 g/mol | Chemical Reagent | Bench Chemicals |
| Angulatin B | Angulatin B, MF:C34H46O15, MW:694.7 g/mol | Chemical Reagent | Bench Chemicals |
Addressing drug-resistant parasites requires coordinated interventions across human, animal, and environmental sectors. The following table summarizes key strategic approaches:
Table 4: One Health Intervention Strategies Against Parasitic AMR
| Intervention Category | Human Health Sector | Animal Health Sector | Environmental Sector |
|---|---|---|---|
| Surveillance & Diagnostics | Strengthen reporting of treatment failures; expand molecular surveillance for resistance markers [64] | Implement AMR monitoring in veterinary parasites; regulate antiparasitic use [64] | Monitor vectors and intermediate hosts for resistance development [65] |
| Drug Stewardship | Implement evidence-based treatment guidelines; restrict over-the-counter antiparasitic sales [64] | Enforce veterinary prescription requirements; phase out prophylactic use [65] | Monitor environmental contamination with antiparasitic drugs [65] |
| Prevention & Control | Improve sanitation infrastructure; promote bed net use; develop vaccines [65] | Implement animal vaccination; improve biosecurity and husbandry [64] | Vector control programs; manage water sources to reduce transmission [63] |
| Policy & Governance | National action plans on AMR; interagency collaboration [64] | Regulate medicated feeds; ban antibiotic growth promoters [65] | Implement wastewater treatment to reduce drug residues [65] |
The "One Health" approach is officially defined as "a collaborative, multisectoral, and transdisciplinary approach â working at the local, regional, national, and global levels â with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment" [2]. This approach is operationalized through frameworks that span the entire antimicrobial lifecycle from research and development to disposal [65]. The newly adopted IUCN Programme 2026â2029, "Nature 2030: One Nature, One Future," further embeds One Health as one of eight global transformations, recognizing its essential role in addressing interconnected health challenges [67].
Successful implementation of these integrated strategies requires breaking down traditional silos between disciplines and sectors. As demonstrated by initiatives like Sri Lanka's rabies control program, which integrated mass canine vaccination, human post-exposure prophylaxis, and public education through cross-sectoral collaboration, this approach can produce dramatic reductions in disease incidence [68]. Similarly, Thailand's "raised-without-antibiotics" initiative in swine farms demonstrates how regulatory approaches can reduce antimicrobial selection pressure [64].
The challenge of drug-resistant parasites represents a complex and evolving threat that demands sustained investigation and intervention through a One Health lens. Future efforts must focus on several critical areas: First, expanding global surveillance systems like WHO's GLASS to include more comprehensive tracking of parasitic AMR [66]. Second, strengthening regulatory frameworks and enforcement mechanisms to ensure appropriate use of antiparasitic agents across human and animal health sectors [64]. Third, investing in research and development for novel therapeutic approaches, including new drug candidates, alternative treatment strategies, and vaccines [69].
The European Partnership on One Health Antimicrobial Resistance (EUP OHAMR), launching its first calls in 2025, represents the type of coordinated international effort required to address these challenges, with over 340 million EUR committed to boost One Health AMR research and innovation [69]. Similarly, academic initiatives like the Southeast Asian One Health Universities Network are crucial for building the next generation of transdisciplinary professionals equipped to tackle parasitic AMR [64].
As climate change, habitat destruction, and increasing global interconnectedness continue to alter parasite-host dynamics, the One Health approach provides an essential framework for developing effective, sustainable solutions to preserve the efficacy of antiparasitic treatments and protect global health security [63] [67].
The One Health approach is an integrated, unifying concept that aims to sustainably balance and optimize the health of people, animals, and ecosystems, recognizing their close interconnection and interdependence [70]. Despite this conceptual framework, the operationalization of One Health faces significant implementation barriers, with cross-sectoral communication breakdowns representing a critical challenge that undermines effective collaboration against wildlife parasitic zoonoses [5] [71] [72]. These breakdowns manifest as fragmented disease reporting systems, isolated data repositories, and disjointed outbreak responses that ultimately compromise public health resilience and zoonotic disease control [73] [30].
Research on zoonotic diseases has disproportionately increased compared to general health studies, with an 18-fold rise in publications nationally and internationally over recent decades [30]. Yet, this growing scientific interest has not translated into effective operational integration. The complex ecology of zoonotic diseases necessitates considering multi-source, multi-agent systems, including host-pathogen community assemblages, environmental reservoirs, and vector involvement [30]. Understanding these complex relationships requires robust communication channels between human, veterinary, and environmental sectorsâchannels that remain underdeveloped in most regions [5] [73].
This technical guide examines the structural, operational, and systemic barriers impeding cross-sectoral communication within the One Health framework, with particular emphasis on implications for wildlife parasitic zoonoses research. It further provides evidence-based solutions and methodological approaches to bridge these disciplinary divides, offering researchers, scientists, and drug development professionals practical tools to enhance collaborative outcomes.
The communication gaps between human, veterinary, and environmental sectors are not merely perceptual but are reflected in quantifiable disparities in infrastructure, resource allocation, and operational capacity. Evaluation of One Health platforms in Guinea revealed an overall performance score of just 41%, with none of the eight assessed regions reaching the 60% performance threshold considered minimal for effective implementation [5]. This performance deficit was particularly pronounced in specific operational domains, as detailed in Table 1.
Table 1: Performance Assessment of One Health Platforms in Guinea Across Key Indicators [5]
| Evaluation Indicator | Performance Score | Key Deficiencies |
|---|---|---|
| Legislation (LID) | 89% (Conakry region) | Variable adoption across regions |
| Material Resources (RMID) | 9% (all regions) | Critical shortage of essential equipment |
| Coordination (CID) | 41% (national average) | Weak formal consultation mechanisms |
| Funding (FID) | Below 60% (all regions) | Lack of dedicated budget lines |
| Training of Actors (FPID) | Below 60% (all regions) | Insufficient training programs |
Similar fragmentation is evident in higher-income settings. In the United States, a survey of 4,144 licensed veterinarians across four states revealed that when faced with unusual infectious diseases in companion animals or livestock, most would notify state agricultural agencies rather than public health entities, with 28% unaware if their community even had a local public health agency [74]. This communication disconnect impedes the recognition of simultaneous human and animal outbreaks, as exemplified by the 1999 West Nile virus outbreak in New York City, where dying crows with neurologic symptoms were observed for a month before the connection was made to human cases [74].
Multiple structural barriers perpetuate these communication breakdowns. Systematic reviews of the literature have identified several categorical obstacles that need to be addressed for successful One Health implementation [72]:
Additional constraints emerge at the professional level. The veterinary profession, for instance, faces structural challenges including corporate consolidation, fee-for-service models that disincentivize non-revenue activities, and significant student debt that pushes graduates toward companion animal practice rather than public health roles [70]. These factors limit veterinarians' capacity to function as One Health communicators despite their strategic position at the human-animal interface.
Communication breakdowns directly impact the effectiveness of surveillance systems and outbreak responses for wildlife parasitic zoonoses. In Guadeloupe, despite the existence of both veterinary and public health surveillance components for West Nile virus, sectoral communication limitations have resulted in a primarily segmented approach that has only recently begun shifting toward integrated surveillance [71]. Similarly, Uruguay demonstrates how systemic gaps in animal welfare regulation and multi-species governance can amplify underreported zoonotic threats, reflecting a structural disconnect between One Welfare principles and policy implementation [73].
The consequences of these disconnects are particularly acute for parasitic diseases in small animals, which pose significant challenges to public health, animal health, and environmental sustainability [75]. As noted in recent parasitology research, "The success of the One Health concept now requires breaking down the interdisciplinary barriers that still separate human and veterinary medicine from ecological, evolutionary, and environmental sciences" [75]. Without integrated communication channels, surveillance systems remain incomplete, compromising early detection and intervention capabilities.
Communication silos create significant knowledge gaps in understanding the complex ecology of zoonotic diseases. In Austria, analysis of 47 years of zoonosis research revealed substantial disparities in investigation focus, with 76.9% of zoonotic agent studies conducted in wildlife hosts, while research on food products predominantly concentrated on animal-origin products, with plant-based foods accounting for only 5.6% of examined foodstuffs [30]. This biased research distribution creates an incomplete picture of transmission pathways and potential reservoirs.
Furthermore, critical environmental aspects were largely neglected in Austrian zoonotic disease studies until 1997, demonstrating the most gradual increase in scientific interest compared to human and animal foci [30]. Such research imbalances directly reflect communication gaps between disciplines and limit comprehensive understanding of the environmental drivers of parasitic zoonoses emergence and transmission.
Network analysis offers a powerful methodological approach for identifying and visualizing communication nodes and pathways within complex zoonotic systems. This approach introduces the concept of a "zoonotic web" â a network representation of zoonotic actors at human-animal-environment interfaces akin to a food web [30]. The methodology for constructing such networks involves systematic data compilation and analytical visualization, as outlined below.
Table 2: Methodological Protocol for Zoonotic Web Network Analysis [30]
| Research Phase | Protocol Description | Output |
|---|---|---|
| Data Collection | Systematic literature search compiling naturally occurring zoonotic interactions across hosts, vectors, food, and environmental sources | Standardized dataset with documented zoonotic interactions |
| Network Construction | Create bipartite network transformed into one-mode projection representing zoonotic agent sharing among sources | Zoonotic web mapping relationships between zoonotic sources |
| Network Analysis | Apply network centrality metrics and community detection algorithms to identify key actors and interfaces | Identification of influential zoonotic sources and transmission communities |
| Interface Identification | Analyze One Health 3-cliques (human, animal, environment) to pinpoint spillover hotspots | Prioritized list of high-risk interfaces for targeted surveillance |
This network-based approach facilitates the development of locally relevant One Health strategies by mapping specific transmission chains and identifying critical control points. The analytical workflow can be visualized as follows:
A structured evaluation framework provides another methodological tool for assessing and improving cross-sectoral communication. Research in Guadeloupe developed and applied an operational OH framework to critically assess collaborative initiatives addressing local health issues [71]. This methodology involves:
This systematic approach moves beyond conceptual discussion to provide actionable insights for enhancing communication and collaboration in existing and future initiatives. The framework is sufficiently flexible to be adapted to various contexts and resource levels.
Effective governance structures are fundamental to overcoming communication barriers. The United States has established a coordinated mechanism through the U.S. One Health Coordination Unit (U.S. OHCU), which involves 24 agencies from eight departments related to public health, agriculture, wildlife, environment, development, international affairs, commerce, defense, and security [72]. This governance model employs several key strategies:
Similarly, Guinea established the National One Health Platform (PNOH) under the supervision of the Ministry of Health, with the main objective of preventing, detecting, and responding to emerging and re-emerging diseases with pandemic potential through a multisectoral approach [5]. These institutional structures provide the foundational framework within which communication can occur.
Barriers to data sharingâincluding privacy concerns, intellectual property rights, institutional barriers, and lack of trustâmust be explicitly acknowledged and addressed through coordinated strategies [72]. Effective solutions include:
Joint training programs help bridge disciplinary gaps by providing opportunities for professionals to learn about each other's expertise and develop common terminology. Specific approaches include:
Table 3: Essential Research Resources for Integrated Wildlife Parasitic Zoonoses Studies
| Research Tool Category | Specific Examples | Application in Zoonoses Research |
|---|---|---|
| Molecular Detection Assays | β-tubulin polymorphism analysis for Trichuris trichiura [75]; Geometric morphometrics for flea population differentiation [75] | Species identification, tracking transmission pathways, detecting genetic markers of resistance |
| Surveillance Materials | Sampling kits; Protective equipment; Data reporting tablets; Visual aid kits [5] | Standardized field sample collection, safe handling of infectious materials, real-time data reporting |
| Bioinformatics Resources | High-performance computing centers; Shared data analysis pipelines [71] [30] | Genomic analysis of pathogen relatedness, integration of multi-sectoral data, modeling transmission networks |
| Diagnostic Reagents | Serological assays; PCR primers/probes; Antigen detection tests [30] [75] | Pathogen detection in human, animal, and environmental samples; outbreak investigation |
| Banked Biological Samples | Archived human and animal sera; Tissue collections; Environmental samples [30] | Retrospective studies, validation of new diagnostics, understanding historical transmission patterns |
Implementing effective communication bridges requires a systematic approach that addresses both technical and social dimensions of collaboration. The following strategic framework synthesizes evidence from multiple case studies and evaluations:
This framework emphasizes that successful communication bridging requires more than technological solutions; it demands institutional commitment, human capacity development, and continuous evaluation and adaptation based on performance metrics and emerging challenges.
Cross-sectoral communication breakdowns represent a critical vulnerability in global defenses against wildlife parasitic zoonoses. These breakdowns are quantifiable, structurally embedded, and have demonstrable consequences for disease surveillance, outbreak response, and research comprehensiveness. However, evidence-based solutionsâincluding network analysis methodologies, structured evaluation frameworks, integrated governance models, shared communication platforms, and interdisciplinary trainingâprovide actionable pathways for bridging these divides.
For researchers, scientists, and drug development professionals working within the One Health paradigm, addressing these communication gaps is not merely administrative but fundamentally scientific. The complex ecology of zoonotic diseases cannot be understood through disciplinary silos alone. By implementing the strategies and methodologies outlined in this technical guide, the scientific community can strengthen the collaborative frameworks necessary to confront the evolving challenge of wildlife parasitic zoonoses in an increasingly interconnected world.
The One Health approach, which recognizes the inextricable links between human, animal, and ecosystem health, is fundamental to addressing zoonotic diseases [1]. Despite this understanding, significant surveillance gaps persist in monitoring pathogens within wildlife, vectors, and environmental reservoirs, creating vulnerabilities for disease emergence and spillover. Current evidence indicates that zoonotic diseases account for approximately 60% of known human infectious diseases and up to 75% of emerging infectious diseases [4] [57] [76]. This technical review, framed within a broader thesis on One Health approaches to wildlife parasitic zoonoses research, examines the critical gaps in current surveillance systems, assesses methodological shortcomings, and proposes integrated strategies to strengthen global health security. The analysis is particularly relevant for researchers, scientists, and drug development professionals working at the intersection of disease ecology and public health.
Several international systems have been established to monitor zoonotic diseases. The Global Early Warning System (GLEWS), a joint initiative of the FAO, OIE, and WHO, represents a significant effort to pool information on animal diseases in high-risk areas [77]. This system functions to track diseases, share information, verify threats, conduct disease analysis, and support outbreak response. Similarly, the World Organisation for Animal Health (OIE) maintains standards across 172 member countries and operates the World Animal Health Information System for data management [77]. The OIE's objectives include encouraging standardized surveillance, safeguarding world trade through health standards, and providing expertise in animal disease control.
The recently developed Global One Health Index for Zoonoses (GOHI-Zoonoses) provides a systematic approach to evaluate One Health performance in zoonosis prevention and control across 160 countries [78]. This tool assesses five key indicators, 16 subindicators, and 31 datasets to identify strengths and weaknesses in responding to zoonotic threats. Correlation analyses have revealed that GOHI-Zoonoses scores associate significantly with economic, sociodemographic, environmental, climatic, and zoological factors, with the Human Development Index being a particularly positive contributor to scores [78].
Table 1: Documented Surveillance Gaps in National Health Security Reports
| Assessment Category | Number of Countries/Reports Analyzed | Key Finding on Wildlife/Environment Inclusion | Percentage with Documented Gaps |
|---|---|---|---|
| Performance of Veterinary Services (OIE) | 32 countries | Variation in wildlife and environmental keyword frequency | 83.2% (89/107) showed operational, coordination, scope, or capacity gaps |
| Joint External Evaluations (WHO) | 91 countries | Limited evidence of functional wildlife health surveillance | 57.9% (62/107) lacked evidence of functional wildlife health surveillance |
| National Action Plans for Health Security | 12 countries | Inconsistent inclusion of environmental factors | Not quantified |
| National Biodiversity Strategies and Action Plans | 125 countries | Minimal inclusion of wildlife health or zoonotic disease | 6.4% (8/125) included tangible wildlife health activities |
A comprehensive review of major health security reports from 107 countries revealed systematic neglect of wildlife and environmental considerations [79]. The analysis demonstrated that more than half (57.9%) of reporting countries provided no evidence of functional wildlife health surveillance programs, while the vast majority (83.2%) indicated specific gaps in operations, coordination, scope, or capacity. This neglect is particularly concerning given that wildlife serves as reservoirs for numerous pathogens with pandemic potential, including Ebola, Marburg, and coronaviruses [79].
Recent evidence syntheses highlight substantial geographical disparities in zoonoses research. A systematic mapping of publications on zoonotic disease risks linked to agrifood systems found that 46% of low- and middle-income countries (LMICs) had no published research on this topic, indicating an uneven distribution of research resources [76] [80]. This gap is particularly alarming given that LMICs often face the highest burden of zoonotic diseases and may harbor the conditions for novel pathogen emergence.
The same analysis revealed that among studied factors influencing zoonotic disease occurrence, research attention has been disproportionately focused on:
Several key areas remain underexplored, including evidence from certain food system contexts using One Health perspectives, wild animal hosts, and how exposure to wild animals may influence disease occurrence in humans and domesticated animals [76].
Table 2: Research Focus Areas in Zoonotic Disease Studies
| Research Category | Percentage of Publications | Key Gaps Identified |
|---|---|---|
| Exposure to potential hosts/vector species | 53% | Limited research on wild animal hosts compared to livestock |
| Social and economic factors | 47% | Inadequate understanding of socioeconomic drivers at human-wildlife interface |
| Physical and environmental factors | 46% | Limited integration of climate change projections |
| Domesticated animal practices | 38% | Insufficient coverage of wildlife-domestic animal interaction |
| Wildlife-specific factors | Not quantified | Major gap in surveillance systems and research focus |
A significant functional gap exists in the translation of surveillance data to actionable insights for decision-makers. Researchers have noted that despite growing recognition of relationships between agricultural practices and zoonotic disease emergence, decision-makers lack evidence-based linkages connecting specific practices to disease risks [76] [80]. This disconnect between research and practical application hinders the development of targeted interventions and policies.
The surveillance of wildlife populations presents particular challenges. As noted in assessments of current systems, there are generally no mandates for reporting disease among wild animals, and die-offs in wild populations may easily be missed [77]. Even when incidents are noticed and reported, local officials may not recognize their significance or know appropriate response steps. The complexity of investigating wildlife disease outbreaks requires multidisciplinary expertise and faces the additional challenge of moving local information to regional, national, and global levels [77].
The research quantifying surveillance gaps employed systematic review methodologies of major health security reports, including WHO Joint External Evaluations, OIE Performance of Veterinary Services reports, and National Action Plans for Health Security [79]. The analytical approach included:
For the assessment of zoonotic disease risks in agrifood systems, researchers conducted systematic mapping of five bibliographic databases and 17 organizational websites [76] [80]. From 49,038 unique publications, 7,839 were identified as potentially relevant using manual screening and machine learning. A 14% random sample (1,034 publications) underwent full-text screening, with 424 included in the final mapping.
Field studies at the human-wildlife interface, such as the research conducted in Hoima District, Uganda, employed cross-sectional mixed methods approaches [81]. The methodology included:
This integrated approach allowed researchers to quantify high-risk behaviors while contextualizing them within local knowledge systems and socioeconomic drivers. The study revealed that 29% of respondents engaged in hunting of wildlife such as chimpanzees, with 55.3% citing animal protein acquisition as the primary motivation and 22.7% reporting cultural or medicinal uses [81].
Table 3: Essential Research Reagents and Materials for Zoonotic Disease Surveillance
| Reagent/Material | Primary Function | Application Context | Technical Considerations |
|---|---|---|---|
| Multiplex PCR assays | Simultaneous detection of multiple pathogens | Wildlife screening, vector surveillance | Requires validation for diverse species; cross-reactivity challenges |
| Next-generation sequencing platforms | Pathogen discovery, genomic characterization | Outbreak investigation, novel pathogen identification | Bioinformatics capacity often limiting in resource-limited settings |
| ELISA kits for wildlife serology | Antibody detection in various species | Sero-surveillance, exposure studies | Limited commercial availability for wildlife species |
| Geographic Information Systems (GIS) | Spatial analysis of disease distribution | Risk mapping, hotspot identification | Integration of environmental, animal, and human data |
| Remote sensing data | Environmental variable monitoring | Climate and land use change impacts | Requires calibration with ground surveillance data |
| Biobanking facilities | Specimen preservation for future study | Pathogen archives, retrospective studies | Ethical considerations for wildlife samples |
| Mobile data collection tools | Field data capture in remote areas | Community-based surveillance | Must be adaptable to low-infrastructure settings |
Effective zoonotic disease surveillance requires specialized reagents and materials adapted to diverse field and laboratory conditions. The validation of diagnostic tools across multiple species presents particular challenges, as commercial assays are typically developed for human or domestic animal use [77]. Furthermore, biobanking of wildlife specimens raises ethical considerations regarding sample ownership and use, particularly when working with endangered species or in collaboration with indigenous communities.
Addressing critical surveillance gaps requires systematic multisectoral collaboration across human, animal, and environmental health sectors [57] [1]. The World Health Organization emphasizes that operationalizing One Health requires shared governance, communication, collaboration and coordination across sectors and disciplines [1]. Specific strategies include:
The Quadripartite collaboration (FAO, UNEP, WHO, WOAH) has developed a comprehensive One Health Joint Plan of Action to mainstream and operationalize One Health approaches at global, regional, and national levels [1]. This initiative aims to support countries in establishing national targets, mobilizing investment, and enabling collaboration across sectors.
Building effective wildlife health surveillance capacity requires addressing fundamental infrastructure and training gaps. Assessments indicate that strengthening wildlife health capacity should be emphasized in One Health efforts to monitor and mitigate known and novel disease risks [79]. Key requirements include:
The One Health High-Level Expert Panel has highlighted the need to improve infrastructure, legal frameworks, and resources for veterinarians and wildlife health professionals [1]. This includes supporting laboratory networks, building veterinary capacity, and engaging both public and private sector stakeholders.
Significant surveillance gaps in wildlife, vector, and environmental monitoring continue to hamper global capabilities for early detection and response to zoonotic disease threats. The inconsistent inclusion of wildlife and environmental health considerations in national health security priorities creates dangerous blind spots in pandemic prevention. Addressing these gaps requires substantive commitment to One Health implementation through strengthened multisectoral collaboration, integrated surveillance systems, and targeted capacity building in under-resourced regions. Future research should focus on developing standardized methodologies for wildlife surveillance, enhancing diagnostic capabilities for diverse species, and creating integrated analytics that bridge human, animal, and environmental data streams. By systematically addressing these surveillance gaps, the global health community can build more resilient systems for detecting and mitigating emerging health threats at the human-animal-environment interface.
This whitepaper outlines a structured framework for equitable resource allocation and capacity building within the context of a "One Health" approach to wildlife parasitic zoonoses research. The increasing global burden of zoonotic diseases, which account for 58% to 61% of all communicable diseases causing illness in humans, necessitates integrated strategies that balance the health of people, animals, and ecosystems [4] [1] [82]. This guide provides researchers and drug development professionals with quantitative methodologies, practical protocols, and a toolkit for prioritizing research initiatives and building sustainable research capacity. By embedding equity at the core of implementation science, we can accelerate the translation of research into effective interventions that address the full spectrum of disease control, from prevention to preparedness and response [83] [1].
The "One Health" approach is an integrated, unifying framework that aims to sustainably balance and optimize the health of people, animals, and ecosystems [1]. It recognizes that the health of these domains are closely linked and interdependent. This is particularly critical for wildlife parasitic zoonoses, where pathogens circulate at the human-animal-environment interface. The emergence of pathogens like SARS-CoV-2 has underlined the urgent need to strengthen this approach, with a greater emphasis on environmental connections [1]. Effective management of these complex threats requires global cooperation, which in turn depends on equitable resource distribution to foster stability, trust, and sustainable solutions [83]. When resources are unevenly distributed, it creates disparities that can lead to resentment, social unrest, and a reluctance to cooperate across borders, ultimately undermining global health security.
A critical first step in equitable resource allocation is the systematic prioritization of diseases and research avenues. This requires moving beyond subjective judgements to quantitative, transparent methods.
Conjoint Analysis (CA) is a market research technique gaining traction in healthcare for eliciting preferences and prioritizing complex issues [4] [82]. It is particularly useful for zoonotic disease prioritization, as it treats a disease as a "product" described by a set of characteristics (criteria) and forces stakeholders to make trade-offs between them, revealing the true relative importance of each criterion [82].
To evaluate and address inequity, researchers must be able to measure it. Several quantitative metrics are available, each with specific applications [84].
Table 1: Key Metrics for Health Inequality Measurement
| Metric | Description | Application | Interpretation |
|---|---|---|---|
| Slope Index of Inequality (SII) | The slope of a regression line predicting a health variable (e.g., healthcare utilization) by socioeconomic rank [84]. | Measures absolute inequality across an entire population distribution. | Represents the difference in utilization between the bottom and top of the socioeconomic scale. |
| Concentration Index | Derived from a concentration curve, which plots the cumulative share of a health variable against the cumulative population ranked by socioeconomic status [84]. | Measures relative socioeconomic-related health inequality. | Ranges from -1 (pro-poor inequality) to +1 (pro-rich inequality); 0 represents perfect equality. |
| Gini Coefficient | Measures the degree of inequality in a distribution, derived from the Lorenz curve [84]. | Summarizes univariate inequality (e.g., inequality in health outcomes alone). | Ranges from 0 (perfect equality) to 1 (perfect inequality). |
| Benefit Incidence Analysis (BIA) | Combines data on unit costs of health services with utilization data across socioeconomic groups [84]. | Evaluates how government health expenditure is distributed across population subgroups. | Reveals whether public spending is progressive (benefiting the poor more) or regressive. |
Advanced methods like Extended Cost-Effectiveness Analysis (ECEA) and Distributional CEA (DCEA) can further help identify interventions that provide the best value for money while reducing health inequities [84]. These techniques incorporate "inequality aversion" parameters, allowing decision-makers to explicitly weight health benefits to the most disadvantaged groups more heavily [84].
Building human and intellectual capital is fundamental for generating new knowledge and narrowing the research-to-practice gap. Effective capacity building requires structured, mentored training programs [85].
The Institute for Implementation Science Scholars (IS-2) provides a proven framework for building capacity with an explicit equity focus [85].
This model demonstrated significant success, with scholars showing gains across 43 implementation science competencies, and the establishment of a vibrant collaborative network. It is notable that under-represented scholars (URS) had similar skill gains, though the study found they were less likely to hold network ties, highlighting an area for continued focus in program design [85].
For researchers in wildlife parasitic zoonoses, a core set of reagents and materials is essential for field and laboratory work. The following table details key items and their functions.
Table 2: Essential Research Reagents and Materials for Wildlife Parasitic Zoonoses Research
| Research Reagent / Material | Function / Application |
|---|---|
| High-Fidelity DNA Polymerase | Accurate amplification of parasite genomic DNA for PCR-based diagnosis and genotyping from human, animal, and environmental samples. |
| Parasite-Specific Monoclonal Antibodies | Detection and quantification of parasitic antigens in clinical (serum) and environmental samples via ELISA and immunohistochemistry. |
| Next-Generation Sequencing (NGS) Library Prep Kits | Preparation of genetic libraries from low-biomass/diverse samples (e.g., wildlife feces, soil, water) for pathogen discovery and microbiome studies. |
| Field DNA/RNA Preservation Buffers | Stabilization of nucleic acids in remote field conditions prior to transport to central laboratories, critical for sample integrity. |
| Recombinant Parasite Antigens | Key reagents for developing highly specific and sensitive serological assays (e.g., ELISA, lateral flow) to detect host exposure. |
| Cell Culture Systems (e.g., primary mammalian, tick, or snail cells) | In vitro modeling of host-parasite interactions, drug screening, and study of parasite life cycle stages. |
| CRISPR-Cas9 Gene Editing Systems | Functional genomic studies to identify and validate essential genes in parasite pathogens, informing novel drug targets. |
| Matrix Standards for Mass Spectrometry | Identification and proteomic profiling of parasites and host responses in tissue samples (MALDI-TOF). |
The following diagram visualizes the logical workflow for implementing the equitable resource allocation and capacity building strategies detailed in this whitepaper, specifically within a One Health research context.
Addressing the complex challenge of wildlife parasitic zoonoses demands a deliberate and systematic approach to equity in resource allocation and capacity building. By adopting quantitative methods like Conjoint Analysis for transparent prioritization and robust inequality metrics for evaluation, the global research community can ensure that limited resources are directed where they are most needed and effective. Coupling this with structured, equity-focused training programs, such as the IS-2 model, builds the necessary human capital to implement solutions. Integrating these strategies within the overarching framework of One Health, as visualized in the provided workflow, creates a resilient, collaborative, and equitable ecosystem for research and implementation. This is not merely an ethical imperative but a pragmatic necessity for achieving global health security and effectively mitigating the impacts of emerging parasitic threats [83] [1] [84].
The One Health approach recognizes the interconnectedness of human, animal, and environmental health and requires robust evaluation frameworks to assess intervention effectiveness. Evaluating One Health interventions presents unique methodological challenges due to the multi-sectoral, multi-level, and multi-stakeholder nature of implementation. Without standardized metrics and methodologies, comparing outcomes across interventions and geographic regions remains problematic, limiting evidence-based policy and practice. This technical guide synthesizes current evaluation frameworks, metrics, and methodologies to standardize the assessment of One Health interventions for wildlife parasitic zoonoses, providing researchers and drug development professionals with practical tools for comprehensive intervention assessment.
The critical need for standardized evaluation is underscored by recent assessments revealing significant gaps in One Health implementation. A systematic scoping review found that while 54.5% of One Health programs involved human and animal sectors only, no studies adequately incorporated the environment sector, highlighting a critical evaluation gap [34]. Furthermore, evaluation studies demonstrated that capacity development and multisectoral coordination were present in 96.1% of programs, but comprehensive monitoring and evaluation strategies were severely underdeveloped [34]. This guide addresses these gaps by providing integrated outcome measures that capture the complex interactions across all three One Health domains.
The Global One Health Index (GOHI) represents the first comprehensive assessment framework evaluating multiple dimensions of One Health across over 160 countries and territories [86]. This framework comprises three main categories: (1) External Drivers Index (EDI), assessing socio-economic, demographic and environmental factors; (2) Internal Drivers Index (IDI), evaluating health services and infrastructure; and (3) Core Drivers Index (CDI), measuring One Health implementation and practices [86]. These categories are further divided into 13 key indices, 57 indicators, and 170 sub-indicators, providing a detailed evaluation structure for identifying vulnerabilities and prioritizing interventions.
Recent research has demonstrated the adaptability of the GOHI framework to sub-national contexts. The Fukuoka One Health Index (FOHI) adaptation in Japan followed a rigorous three-phase methodology: (1) Indicator Selection through expert consultation and Delphi method; (2) Data Collection and Score Standardization using robust scaling methods; and (3) Weight Determination using Fuzzy Analytic Hierarchy Process [86]. The resulting evaluation revealed a mean FOHI score of 52.27 (range: 41.01-63.71), with the lowest average score in Core Drivers Index (47.11) compared to Internal Drivers Index (59.17) and External Drivers (50.43) [86]. Municipalities performed strongest in zoonotic disease management (72.33) but weakest in One Health governance (6.36), demonstrating the framework's ability to identify specific implementation gaps [86].
Table: Fukuoka One Health Index (FOHI) Assessment Results
| Index Category | Average Score | Strength Indicators | Weakness Indicators |
|---|---|---|---|
| Core Drivers Index (CDI) | 47.11 | Zoonotic disease management (72.33) | One Health governance (6.36) |
| Internal Drivers Index (IDI) | 59.17 | Health infrastructure | Laboratory capacity |
| External Drivers Index (EDI) | 50.43 | Environmental factors | Socio-economic determinants |
The Quadripartite collaboration (FAO, UNEP, WHO, WOAH) developed the One Health Joint Plan of Action (OH JPA) Theory of Change framework, structured across three pathways and six action tracks to achieve "sustainable health and food systems, reduced global health threats and improved ecosystem management" [34]. The three pathways include: (1) Policy, legislation, advocacy and financing; (2) Organizational development, implementation and sectoral integration; and (3) Data, evidence and knowledge [34].
A systematic analysis of 54 One Health implementation studies revealed that 90.9% of programs incorporated at least one aspect of Pathway 1, 96.1% incorporated Pathway 2, but only 60% incorporated Pathway 3 [34]. This analysis demonstrates that capacity development and multisectoral coordination form the foundation of One Health implementation, while data, evidence, and knowledge systems remain underdeveloped, highlighting a critical area for methodological improvement in intervention evaluation.
In Guinea, a cross-sectional study of regional One Health platforms utilized a standardized evaluation tool developed by Africa CDC to assess performance across eight administrative regions [5]. The evaluation focused on seven key indicators: (1) Legislation; (2) Epidemic Detection and Documentation; (3) Preparedness; (4) Training of Actors; (5) Material Resources; (6) Funding; and (7) Coordination [5]. The study revealed an overall One Health performance score of 41%, indicating limited implementation at the national scale, with no region reaching the 60% performance threshold [5].
Table: One Health Platform Performance in Guinea by Indicator
| Performance Indicator | Average Score | Highest Performing Region | Lowest Performing Region |
|---|---|---|---|
| Legislation | 62% | Conakry (89%) | Labé (45%) |
| Epidemic Detection & Documentation | 53% | Conakry (78%) | Kindia (35%) |
| Preparedness | 48% | Boké (72%) | Faranah (31%) |
| Training of Actors | 51% | N'zérékoré (75%) | Labé (32%) |
| Material Resources | 9% | Conakry (21%) | Kindia (2%) |
| Funding | 29% | Conakry (55%) | Labé (12%) |
| Coordination | 57% | Conakry (82%) | Faranah (38%) |
Indicator-level analysis revealed significant heterogeneity across regions, with Conakry demonstrating strong performance in legislation (89%), while all regions exhibited weak capacities in mobilizing material resources (9%) [5]. This evaluation approach provides a pragmatic methodology for identifying critical system gaps in resource-limited settings, particularly useful for prioritizing interventions in wildlife parasitic zoonoses research where resources are often constrained.
Rapid and comprehensive data sharing is vital to the transparency and actionability of wildlife infectious disease research and surveillance. A recently proposed minimum data and metadata reporting standard for wildlife disease studies identifies 40 data fields (9 required) and 24 metadata fields (7 required) sufficient to standardize and document a dataset consisting of records disaggregated to the finest possible spatial, temporal, and taxonomic scale [87] [88]. This standard addresses critical gaps in current practice, where most studies only provide summary statistics for parasite prevalence across different sites, species, or time points, which cannot be disaggregated back to the host level [87].
The guiding philosophy of the data standard is that researchers should share their raw wildlife disease data in a format that data scientists refer to as "rectangular data" or "tidy data," where each row corresponds to a single measurement, specifically the outcome of a diagnostic test [87]. The three main categories of information include: (1) Sample data (Sample ID, Collection date, Latitude, Longitude); (2) Host animal data (Host identification, Organism sex, Life stage, Mass); and (3) Parasite data (Parasite taxonomic name, Test result, Test name) [87]. This standardized approach enables more robust meta-analyses and comparative studies essential for evaluating interventions across different ecological contexts.
Network analysis approaches provide powerful methodologies for understanding complex zoonotic interactions and evaluating intervention effectiveness. The concept of "zoonotic web" (akin to "food web") represents a network representation of zoonotic actors at human-animal-environment interfaces intended for use in One Health approaches [30]. This methodology was applied in Austria, where a systematic literature search compiled a dataset of naturally occurring zoonotic interactions spanning 1975-2022, creating a bipartite network transformed into a one-mode projection representing the network of zoonotic agent sharing among zoonotic sources [30].
The analysis revealed that within the projected unipartite source-source network of zoonotic agent sharing, the most influential zoonotic sources were human, cattle, chicken, and some meat products [30]. Analysis of the One Health 3-cliques (triangular sets of nodes representing human, animal, and environment) confirmed the increased probability of zoonotic spillover at human-cattle and human-food interfaces [30]. The study characterized six communities of zoonotic agent sharing, whose assembly patterns are likely driven by highly connected infectious agents in the zoonotic web, proximity to human, and anthropogenic activities [30]. This network methodology offers researchers a sophisticated approach for identifying critical intervention points in complex ecological systems.
Based on the successful implementation in Fukuoka, Japan, the following protocol provides a standardized methodology for evaluating One Health interventions targeting wildlife parasitic zoonoses:
Phase 1: Indicator Selection and Adaptation
Phase 2: Data Collection and Standardization
Phase 3: Weight Determination and Score Calculation
Phase 4: Performance Analysis and Interpretation
For understanding intervention impacts on complex ecological relationships, the following protocol adapts the zoonotic web methodology:
Data Compilation Phase
Network Construction Phase
Community Analysis Phase
Intervention Simulation Phase
Table: Essential Research Reagents and Materials for One Health Intervention Evaluation
| Category | Item | Specification/Standard | Application in Evaluation |
|---|---|---|---|
| Data Collection Tools | Standardized wildlife disease data collection form | 40 data fields (9 required), 24 metadata fields (7 required) [87] | Ensures consistent, comparable data collection across studies and sites |
| Diagnostic Reagents | Pathogen detection kits | PCR, ELISA, or other standardized tests with documented sensitivity/specificity | Case detection and confirmation; must include positive and negative controls |
| Geospatial Materials | GPS devices | Minimum accuracy of 5 meters | Precise location data for spatial analysis of zoonotic distributions |
| Sample Collection | Biological sample collection kits | Swabs, containers, preservatives appropriate for pathogen survival | Standardized sample integrity across collection sites and personnel |
| Data Management | FAIR-compliant database system | PHAROS database, GBIF, or custom solutions with API access | Data integration, sharing, and re-use across research communities |
| Analysis Software | Network analysis packages | igraph, NetworkX, or specialized zoonotic web tools | Mapping complex interactions across human-animal-environment interfaces |
| Reference Materials | Standardized indicator frameworks | GOHI, OH JPA, or adapted local versions (e.g., FOHI) | Comparative assessment across temporal and spatial scales |
Evaluating One Health interventions for wildlife parasitic zoonoses requires integrated, standardized outcome measures that capture the complex interactions across human, animal, and environmental health domains. The frameworks, metrics, and methodologies presented in this technical guide provide researchers and drug development professionals with robust tools for comprehensive intervention assessment. The Global One Health Index adaptation methodology offers a structured approach for local context customization, while the zoonotic web analysis enables understanding of complex ecological relationships that drive disease transmission.
Future development in One Health intervention evaluation should focus on enhancing the environmental health component, which remains underrepresented in current implementations [34]. Additionally, greater emphasis on standardized data collection and negative result reporting will enable more robust meta-analyses and systematic reviews [87] [88]. As evaluation methodologies mature, establishing clear linkages between One Health interventions and quantifiable outcomes across all three domains will be essential for justifying continued investment and policy support for integrated approaches to managing wildlife parasitic zoonoses.
The operationalization of these evaluation frameworks at local levels, as demonstrated in Fukuoka, Japan, and Guinea, provides promising models for contextually relevant assessment while maintaining global comparability [86] [5]. By adopting these standardized metrics and methodologies, the One Health research community can generate the compelling evidence base needed to advance the field and effectively address the complex challenge of wildlife parasitic zoonoses in an increasingly interconnected world.
Zoonotic diseases, which are transmitted between animals and humans, present complex challenges to global public health. This whitepaper provides a comparative analysis of three significant zoonosesâRabies, Cystic Echinococcosis (CE), and Zoonotic Tuberculosis (TB)âwithin the context of the One Health framework. The One Health approach recognizes the interconnectedness of human, animal, and environmental health and is critical for developing effective control strategies for these diseases [89] [90]. Each of these diseases has distinct transmission dynamics, epidemiological profiles, and control requirements, yet they all share the common feature of requiring coordinated cross-sectoral interventions. This analysis synthesizes current burden data, control methodologies, and research protocols to inform researchers, scientists, and drug development professionals working at the interface of human, animal, and environmental health.
The global burden of these three zoonotic diseases varies significantly in terms of incidence, mortality, and geographical distribution. Understanding these epidemiological profiles is essential for prioritizing and targeting control interventions effectively.
Table 1: Comparative Global Burden of Zoonotic Diseases
| Disease | Global Incidence (ASIR) | Global Mortality (ASMR) | Primary Reservoir | Key High-Burden Regions |
|---|---|---|---|---|
| Rabies | Not specified in results | ~100% fatal after symptoms [91] | Domestic dogs (99% of human cases) [91] | Timor-Leste, Indonesia, Africa [91] |
| Cystic Echinococcosis (CE) | 1.82 per 100,000 (2021) [92] | 0.02 per 100,000 (2021) [92] | Dogs (definitive host), Sheep/Livestock (intermediate) [93] | Southern Latin America, Central Asia, East Asia [92] |
| Zoonotic Tuberculosis | Detection rates 0.77%-49% in dairy studies [90] | Contributes to overall TB burden (1.4M deaths, 2020) [90] | Cattle (primarily), Wildlife reservoirs [94] | Ethiopia, Mexico, Tanzania, India [90] |
Table 2: Disparities in Disease Burden by Socio-Demographic Index (SDI)
| Disease | Low-SDI Regions | High-SDI Regions | Temporal Trends |
|---|---|---|---|
| Rabies | Limited PEP access, higher fatalities [91] | Dog rabies free since 2007 (e.g., U.S.) [95] | Ongoing outbreaks in naive populations [91] |
| Cystic Echinococcosis | ASPR = 9.88 per 100,000 [92] | ASPR = 1.67 per 100,000 [92] | ASPR stable, ASMR declining (EAPC: -4.83%) [92] |
| Zoonotic Tuberculosis | Higher prevalence due to unpasteurized dairy consumption [90] | Rare due to pasteurization, veterinary controls [90] | Persists in endemic areas with limited veterinary infrastructure [90] |
Rabies control exemplifies a successful One Health approach that integrates veterinary and human public health measures. The fundamental strategy involves breaking the transmission cycle from dogs to humans through coordinated interventions.
Dog Vaccination: The cornerstone of rabies control is achieving â¥70% vaccination coverage in dog populations to establish herd immunity and interrupt transmission [91]. Current limitations include low coverage (e.g., 24% in Indonesia, 2022) and significant stray dog populations [91].
Post-Exposure Prophylaxis (PEP): For human exposure, PEP is nearly 100% effective if administered promptly and correctly. The protocol includes: (1) extensive wound washing with soap and water for at least 15 minutes; (2) a course of modern cell-culture rabies vaccines that meet WHO standards; and (3) infiltration of rabies immunoglobulin (RIG) or monoclonal antibodies into the wound for Category III exposures [91]. Limitations in PEP access and completion, particularly in remote areas, contribute to ongoing fatalities [91].
Innovative Tools: The market is seeing advances including recombinant nanoparticle-based formulations, monoclonal antibody cocktails, and thermostable human rabies immune globulin [96]. Intradermal administration routes and single-dose cell-culture vaccines are improving accessibility [96].
CE control requires integrated approaches targeting the parasite's complex lifecycle between definitive hosts (dogs) and intermediate hosts (typically livestock).
Veterinary Interventions: Regular deworming of dogs with praziquantel and livestock vaccination with EG95 vaccine are primary control measures [92]. These interventions reduce egg shedding from infected dogs and break the transmission cycle to intermediate hosts.
Public Health Measures: Community education focuses on hygiene practices to prevent exposure to Echinococcus eggs from dog feces, particularly for children in endemic areas [93]. Safe slaughtering practices and proper offal disposal prevent dogs from accessing infected livestock tissues [92].
Challenges: Control efforts face challenges from suboptimal medical conditions, inadequate prevention measures, and insufficient resources in endemic regions [93]. Despite various control strategies, CE continues to pose a serious public health threat in many regions [93].
Zoonotic TB control, primarily caused by Mycobacterium bovis, requires integrated approaches across human health, animal health, and food safety sectors.
Food Safety Interventions: Pasteurization of milk is the most effective intervention to prevent transmission through dairy products [90]. Enforcement of food safety regulations and public campaigns against unpasteurized dairy consumption are critical, particularly in endemic regions.
Veterinary Health Measures: Test-and-cull programs for infected cattle, movement controls, and regular bovine TB testing are essential veterinary components [90]. Strengthening veterinary infrastructure in low-resource settings is crucial for effective control.
Diagnostic Challenges: Zoonotic TB detection faces significant heterogeneity (I² = 98.9%) due to inconsistent testing standards and study designs [90]. Molecular methods like PCR show higher sensitivity (up to 49%) compared to culture techniques (21%-35%) [90].
Robust surveillance systems are fundamental for understanding disease distribution and burden. The following protocols represent standardized methodologies for zoonotic disease assessment.
Table 3: Core Surveillance Methodologies for Zoonotic Diseases
| Methodology | Key Applications | Implementation Steps | Data Outputs |
|---|---|---|---|
| CDC Rabies Assessment Protocol [95] | Country-level rabies status classification | 1. Review public data (WHO, WOAH, PAHO) 2. Evaluate surveillance robustness 3. Assess PEP availability 4. Classify country status | Lyssavirus-free, robust surveillance, control program status |
| GBD Database Analysis [93] [92] | CE burden estimation across 204 countries | 1. Extract age-specific data 2. Calculate age-standardized rates (ASRs) 3. Compute EAPCs 4. Project future trends (ARIMA modeling) | Prevalence, incidence, mortality, DALYs, and projections |
| Zoonotic TB Meta-Analysis [90] | Prevalence estimation from dairy consumption | 1. Systematic literature search (2000-2024) 2. Data extraction 3. Heterogeneity assessment (Cochran's Q, I²) 4. Pooled prevalence calculation (random/fixed effects) | Pooled detection rates, subgroup analyses, bias assessment |
Accurate diagnosis is essential for clinical management, surveillance, and control of zoonotic diseases. The following workflows outline standard diagnostic approaches.
Diagram 1: Diagnostic Pathways for Zoonotic Diseases
Evaluating the implementation of One Health approaches in research requires systematic assessment of integration across domains.
Diagram 2: One Health Implementation in Zoonoses Research
The following table details essential research reagents and materials for investigating these zoonotic diseases, facilitating standardized research protocols across laboratories.
Table 4: Essential Research Reagents for Zoonotic Disease Studies
| Reagent/Material | Specific Application | Function in Research |
|---|---|---|
| RT-PCR Assays [91] | Rabies virus confirmation | Detection of viral RNA in saliva, skin, or brain samples for case confirmation and surveillance |
| Cell-Culture Rabies Vaccines [95] [96] | PEP evaluation and research | Gold-standard vaccines for immunogenicity studies and protection evaluation in research models |
| Monoclonal Antibody Cocktails [96] | Rabies research and treatment | Neutralizing antibodies for passive immunization research and therapeutic development |
| EG95 Recombinant Vaccine [93] | CE intervention studies | Protein-based vaccine for intermediate host immunization in transmission interruption studies |
| Praziquantel [92] | CE control research | Anthelmintic for deworming protocols in definitive hosts (dogs) for transmission reduction studies |
| Mycobacterium bovis RD-deletion Markers [90] | Zoonotic TB differentiation | Molecular markers to distinguish M. bovis from M. tuberculosis in diagnostic assay development |
| Selective Culture Media (L-J) [90] | Zoonotic TB isolation | Culture medium for M. bovis isolation from clinical samples with characteristic biochemical profiling |
| PCR Primers for Echinococcus spp. [93] | CE species identification | Genetic markers for species and strain differentiation in epidemiological studies and life cycle tracking |
| Rapid Immunochromatographic Tests [96] | Field-based diagnostics | Point-of-care detection of pathogens or antibodies for surveillance in resource-limited settings |
| ELISA Kits (IgG/IgM) [96] | Seroprevalence studies | Detection of host immune response to pathogens for exposure assessment and epidemiological studies |
The comparative analysis of rabies, CE, and zoonotic TB reveals critical insights for advancing One Health approaches to zoonotic disease control. While each disease has unique characteristics, common challenges and opportunities for integration emerge across all three.
Current research on zoonotic diseases demonstrates significant gaps in implementing truly integrated One Health approaches. A systematic review found that only 4.8% of studies on zoonotic risks in wildlife simultaneously integrated human, animal, and environmental domains in data collection, with just 29.5% integrating these domains in knowledge generation [89]. Environmental health is particularly underrepresented (34.3% of studies), while social science methodologies are used in only 19% of studies [89]. This fragmentation impedes comprehensive understanding of disease dynamics and limits the effectiveness of control strategies. Future research should prioritize transdisciplinary collaboration that equally weights all three One Health domains.
Technological innovations are reshaping approaches to zoonotic disease control. For rabies, recombinant nanoparticle-based formulations and monoclonal antibody cocktails are advancing treatment options [96]. Intradermal vaccination routes and thermostable formulations are improving accessibility in resource-limited settings [96]. For CE, the declining mortality trends (EAPC: -4.83%) demonstrate progress in clinical management, though stable incidence highlights the need for improved transmission interruption [92]. For zoonotic TB, molecular methods like PCR are demonstrating superior sensitivity (up to 49%) compared to traditional culture techniques (21%-35%) [90], though standardization remains challenging, as evidenced by significant heterogeneity (I² = 98.9%) in detection studies.
The burden of all three diseases demonstrates strong socioeconomic gradients. CE shows a strong negative correlation between Socio-demographic Index (SDI) and health indicators, with low-SDI regions bearing the highest burden (ASPR = 9.88 per 100,000 vs. 1.67 in high-SDI regions) [92]. Similarly, zoonotic TB disproportionately affects vulnerable populations with limited access to pasteurization facilities and veterinary services [90]. Rabies fatalities occur mainly among those who cannot immediately access effective PEP, with significant disparities in RIG availability between urban and rural areas [95] [91]. These equity considerations must be central to the design and implementation of control programs.
Based on this comparative analysis, three strategic priorities emerge for advancing One Health approaches to these zoonoses:
Strengthening Integrated Surveillance: Developing unified surveillance systems that simultaneously monitor human, animal, and environmental parameters would enhance early detection and response capabilities. The CDC's rabies assessment protocol provides a model for systematic data collection and classification that could be adapted for other zoonoses [95].
Advancing Accessible Countermeasures: Innovations such as thermostable vaccines, single-dose regimens, and point-of-care diagnostics are critical for expanding access in resource-limited settings. The ongoing development of monoclonal antibody cocktails for rabies treatment exemplifies this direction [96].
Promoting Cross-Sectoral Coordination: Effective zoonoses control requires breaking down silos between human health, animal health, and environmental sectors. Timor-Leste's establishment of a National Task Force on Rabies adopting a One Health approach demonstrates the potential of coordinated responses [91].
This comparative analysis underscores the critical importance of One Health approaches in addressing the complex challenges posed by rabies, cystic echinococcosis, and zoonotic tuberculosis. While these diseases differ in their transmission dynamics, clinical manifestations, and geographical distributions, they share common requirements for coordinated, cross-sectoral interventions. Significant progress has been made in reducing mortality for CE and developing innovative tools for rabies, but persistent disparities in disease burden between high- and low-SDI regions highlight the need for equitable implementation of control strategies. The continued emergence of zoonotic diseases, as demonstrated by Timor-Leste's recent rabies outbreak [91], reinforces the importance of robust, integrated surveillance and response systems. By advancing transdisciplinary research, strengthening health systems, and promoting equitable access to countermeasures, the global community can make significant progress toward reducing the burden of these neglected zoonotic diseases.
This whitepaper provides a technical guide for conducting economic impact assessments of preventive versus reactive approaches to wildlife parasitic zoonoses within a One Health framework. It details methodologies for quantitative data collection, analytical frameworks for cost-benefit calculation, and visualization tools to support decision-making by researchers, scientists, and drug development professionals. The guidance emphasizes capturing cross-sectoral costs and benefits across human, animal, and environmental health domains to build a compelling economic case for proactive investment.
The One Health approach is defined as "an integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems" by mobilizing "multiple sectors, disciplines and communities at varying levels of society to work together" [97]. One Health Economics extends this approach by estimating costs and benefits that account for multiple sectors to provide a more comprehensive understanding of human, animal, and environment links than can be achieved with single-sector economic analyses alone [97]. For wildlife parasitic zoonoses, this is particularly critical because effective interventions often lie outside the human health sector, as transmission typically occurs from animals to humans rather than between humans [97].
Economic impacts from zoonotic diseases extend far beyond direct control costs. They include direct decreases in household income from lower livestock/product sales, consumption impacts from reduced food security, and increased household vulnerability where livestock serve as a risk-coping mechanism and affect household wealth [97]. Reactive approaches often focus solely on containment and treatment costs, while neglecting the substantial societal benefits of preventing outbreaks before they occur. This whitepaper establishes methodologies to comprehensively evaluate these economic relationships.
Within the context of wildlife parasitic zoonoses, preventive approaches encompass interventions implemented before disease emergence or spread to reduce risk and potential impact. These include wildlife surveillance programs, ecosystem management to reduce transmission interfaces, veterinary interventions in reservoir species, and pre-emptive vaccination campaigns. In contrast, reactive approaches are implemented after disease detection in human or animal populations and include outbreak investigation, human treatment, emergency animal culls, and trade restriction management.
The economic distinction between these approaches fundamentally concerns the temporal allocation of resources and the magnitude of potential losses. Preventive strategies typically require earlier investment for uncertain future benefits, while reactive approaches often incur delayed but potentially far greater costs during crisis response. A One Health economics lens is essential because the costs of prevention may fall primarily on one sector (e.g., environmental or animal health) while benefits accrue predominantly to another (e.g., human health) [97].
Full Societal Costs: Comprehensive evaluation must include both private and public costs across health, agriculture, and environment sectors, including costs to households [97]. Reactive approaches often incur significant negative externalities such as impacts on other producers, human health, and animal welfare [97].
Time Value of Money: Future costs and benefits must be discounted to present values using the formula:
PV = FV/(1+r)^n
where PV is present value, FV is future value, r is the discount rate, and n is the number of periods [98]. This is particularly important for preventive approaches where costs are immediate but benefits accrue over years.
Opportunity Costs: Resources allocated to either preventive or reactive approaches have alternative uses that must be considered in economic evaluation [99].
Cross-Sectoral Cost-Benefit Allocation: Effective analysis requires mapping how costs and benefits distribute across different sectors and stakeholders, identifying potential co-benefits and trade-offs of interventions [97].
Cost-benefit analysis (CBA) is "the process of comparing the projected or estimated costs and benefits associated with a project decision to determine whether it makes sense from a business perspective" [99]. For One Health applications, this framework must be expanded to incorporate cross-sectoral impacts. The systematic process involves four key steps:
Establish the Analysis Framework: Define goals, objectives, and metrics for success specific to the zoonotic disease context. Identify all relevant stakeholders across human health, animal health, environmental, and economic sectors [99]. Determine the appropriate timeframe for analysis, considering the ecology of the parasite and potential lag times between intervention and effect.
Identify Costs and Benefits: Compile exhaustive lists of all potential costs and benefits categorized as follows [99]:
Assign Monetary Values: Where possible, assign appropriate dollar values to all identified costs and benefits. This requires careful consideration of valuation techniques for non-market goods such as ecosystem services and biodiversity preservation.
Calculate and Compare Net Benefits: Tally total values and compute the cost-benefit ratio using the formula [98]:
Cost-Benefit Ratio = Sum of Present Value Benefits / Sum of Present Value Costs
A ratio greater than 1 indicates a positive return on investment.
Comprehensive economic assessment requires integration of diverse data types across the One Health spectrum. The following table outlines essential data categories and collection approaches:
Table 1: Data Requirements for One Health Economic Impact Assessment
| Data Category | Preventive Approach Metrics | Reactive Approach Metrics | Collection Methods |
|---|---|---|---|
| Human Health | Averted morbidity/mortality; reduced treatment costs; productivity preservation | Disease incidence; hospitalization rates; treatment costs; productivity losses | Health facility records; household surveys; demographic surveillance |
| Animal Health | Wildlife surveillance costs; reservoir population management expenses; veterinary interventions | Domestic animal morbidity/mortality; livestock productivity losses; veterinary treatment costs | Veterinary reports; wildlife monitoring; livestock producer surveys |
| Environmental | Ecosystem management costs; habitat modification expenses; biodiversity preservation benefits | Environmental contamination control costs; ecosystem degradation losses | Remote sensing; ecological field studies; environmental quality monitoring |
| Economic & Trade | Program administration costs; international collaboration expenses | Trade restrictions impacts; market disruptions; response program implementation costs | Economic statistics; trade records; market analyses; stakeholder interviews |
For complex zoonotic systems with limited historical data, several modelling approaches can be employed:
The economic comparison between preventive and reactive approaches requires systematic quantification of all relevant cost and benefit categories. The following tables provide templates for this assessment, with illustrative examples from literature.
Table 2: Cost-Benefit Analysis Framework for Preventive Approaches
| Cost/Benefit Category | Human Health Sector | Animal Health Sector | Environmental Sector | Economic Sector |
|---|---|---|---|---|
| Direct Costs | Vaccination programs; prophylactic treatment; public health education | Wildlife surveillance; reservoir host management; domestic animal vaccination | Ecosystem monitoring; habitat modification | Program administration; international collaboration |
| Indirect Costs | Training healthcare workers; surveillance system maintenance | Research and development; diagnostic capacity building | Protected area management; biodiversity conservation | Economic incentives for compliance; public awareness campaigns |
| Direct Benefits | Averted treatment costs; reduced morbidity and mortality | Reduced veterinary costs; maintained livestock productivity | Preserved ecosystem services; maintained biodiversity | Sustained trade; tourism revenue; market stability |
| Indirect Benefits | Increased productivity; reduced caregiver burden | Food security; sustained livelihoods | Climate resilience; water quality protection | Avoided emergency response costs; economic resilience |
Table 3: Cost-Benefit Analysis Framework for Reactive Approaches
| Cost/Benefit Category | Human Health Sector | Animal Health Sector | Environmental Sector | Economic Sector |
|---|---|---|---|---|
| Direct Costs | Outbreak investigation; case management; emergency response | Animal testing; culling; quarantine implementation | Environmental decontamination; remediation | Trade restrictions; market losses; compensation payments |
| Indirect Costs | Long-term disability care; chronic health conditions | Repopulation programs; breeding stock loss | Ecosystem restoration; species reintroduction | Economic stimulus requirements; business failures |
| Direct Benefits | Disease containment; reduced further transmission | Outbreak control; reduced further spread | Contamination control; reduced further degradation | Eventually restored trade; economic recovery |
| Indirect Benefits | Immune population development; system strengthening | Improved biosecurity awareness; system strengthening | Enhanced regulatory frameworks; monitoring improvements | Lessons learned for future preparedness |
Empirical evidence demonstrates the economic advantage of preventive approaches. The 2010 Rift Valley Fever outbreak in South Africa resulted in production losses of approximately R5.4 million among surveyed farmers, with district-level losses ranging between R625,444 and R51.7 million in the Eastern Cape, Free State and Northern Cape provinces [97]. These were conservative estimates accounting only for livestock production, excluding human health costs and broader economic impacts.
A foot-and-mouth disease outbreak in South Africa in 2022 resulted in a 12% decrease in beef exports and a 21% decrease in wool exports due to temporary closure of various export markets [97]. Such trade impacts often far exceed direct disease management costs but are frequently overlooked in single-sector analyses.
Table 4: Essential Research Reagents and Materials for One Health Zoonoses Research
| Reagent/Material | Technical Function | Application in Economic Assessment |
|---|---|---|
| Species-Specific Diagnostic Kits | Serological and molecular detection of parasitic infections in wildlife reservoirs | Quantify disease prevalence in animal populations for risk assessment and surveillance cost estimation |
| Environmental DNA (eDNA) Sampling Tools | Detection of parasite material in environmental samples (water, soil) | Monitor environmental contamination and evaluate intervention effectiveness in ecosystem management |
| Geographic Information Systems (GIS) | Spatial analysis of disease distribution and ecological factors | Identify high-risk areas for targeted interventions and optimize resource allocation |
| Multi-Host Transmission Models | Mathematical modeling of parasite flow between wildlife, domestic animals, and humans | Predict outbreak dynamics and magnitude for cost projections of reactive scenarios |
| Economic Input-Output Models | Tracing economic interdependencies across sectors | Quantify ripple effects of disease outbreaks throughout the economy |
| Stochastic Simulation Platforms | Incorporating uncertainty into outcome projections | Model probability distributions of costs and benefits for robust economic evaluation |
Problem Scoping and Stakeholder Identification
Intervention Definition and Characterization
Epidemiological and Ecological Parameter Estimation
Cost Data Collection and Validation
Benefit Estimation and Valuation
Model Building and Analysis
Uncertainty and Sensitivity Analysis
Result Interpretation and Recommendation Development
The economic evidence consistently demonstrates the superiority of preventive approaches for managing wildlife parasitic zoonoses within a One Health framework. However, implementation requires addressing several practical challenges:
The methodology outlined in this whitepaper provides researchers, scientists, and drug development professionals with the technical tools to build a compelling economic case for preventive investment, ultimately contributing to more sustainable and resilient health systems through the One Health approach.
Nipah virus (NiV) represents a significant zoonotic threat with case fatality rates ranging from 40% to 75%, highlighting the critical importance of effective outbreak control strategies [100] [101]. This technical analysis examines documented failures in risk communication during NiV outbreaks and identifies the transition to successful, evidence-based interventions. Evidence from Bangladesh demonstrates that initial one-way communication approaches that disregarded local cultural contexts were largely ineffective, leading to community resistance and continued high-risk behaviors [102]. Subsequent implementation of culture-centered communication strategies that incorporated local beliefs and practices resulted in significantly improved acceptance of prevention messages [102]. The integration of these communication principles within a One Health frameworkâaddressing the interconnectedness of human, animal, and environmental healthâprovides an essential paradigm for managing NiV and other emerging zoonotic threats [89] [2].
Nipah virus is a paramyxovirus of the genus Henipavirus, first identified during outbreaks in Malaysia and Singapore in 1998-1999 [100] [103]. As a biosafety level-4 (BSL-4) pathogen, NiV requires the highest level of containment, reflecting its significant public health risk [101]. The virus circulates naturally in fruit bats of the Pteropus genus, which act as asymptomatic reservoir hosts, creating persistent zoonotic potential across South and Southeast Asia [101] [103].
The One Health approach recognizes that optimal health outcomes depend on the interconnected health of people, animals, and the shared environment [2]. This framework is particularly relevant to NiV management, as outbreaks often result from complex interactions between wildlife reservoirs, human behavioral practices, and environmental changes such as deforestation and altered land use [89] [2]. Despite its classification as a WHO priority pathogen with epidemic potential, NiV has received comparatively limited bioethical and communication research attention, creating critical gaps in outbreak response capabilities [100].
During a 2010 NiV outbreak in Faridpur District, Bangladesh, initial risk communication efforts by health authorities failed to achieve community cooperation [102]. Traditional communication methods included broadcast announcements via loudspeakers and household visits advising residents to stop consuming raw date palm sap, a known transmission route for the virus [102]. Despite these efforts, community residents continued high-risk behaviors, including raw sap consumption and maintaining practices that facilitated human-to-human transmission during caregiving [102].
Table: Initial Communication Failures in Nipah Virus Outbreaks
| Failure Aspect | Traditional Approach | Community Response |
|---|---|---|
| Message Content | One-way recommendation to stop raw sap consumption | Rejection of message due to lack of causal explanation |
| Communication Channel | Loudspeakers, household visits | Perceived as authoritative without engagement |
| Cultural Context | Disregarded local beliefs and practices | Reinforcement of traditional explanations and resistance to biomedical advice |
| Trust Level | Low trust in public healthcare system | Suspicion of health authorities and hospital workers |
Analysis revealed several fundamental flaws in the initial communication strategy:
Supernatural Explanations: Community members predominantly attributed the outbreak to supernatural forces, including "punishment from Allah" or other metaphysical causes, rather than viral transmission [102]. The lack of effective treatment for NiV-infected patients reinforced these non-biomedical explanations.
Incomplete Messaging: Initial prevention messages failed to explain how bats transmitted the virus or provide visual evidence of the contamination process [102]. This created a critical knowledge gap that undermined message credibility.
Cultural Norms Conflict: Public health recommendations to avoid close contact with infected patients directly contradicted strong cultural obligations for family members to provide hands-on care during illness [100] [102]. Similarly, advice against raw sap consumption failed to acknowledge its significance as a traditional delicacy with cultural importance [100].
Biomedical Distrust: High case fatality rates and ineffective medical treatment eroded trust in the healthcare system, with community members becoming suspicious of hospital workers and biomedical explanations [102].
Field anthropologists implemented a redesigned communication strategy based on anthropological methods and culturally-centered engagement [102]. This approach involved two systematic phases:
Phase 1: Ethnographic Investigation
Phase 2: Interactive Message Development
Table: Effectiveness and Cost Analysis of Nipah Prevention Strategies
| Intervention Approach | Implementation Cost | Reach Scale | Key Outcomes | Cost for 30-District Scale-Up |
|---|---|---|---|---|
| "No Raw Sap" Approach | $30,000 | 342 villages | Increased knowledge of NiV transmission; reduced raw sap consumption | ~$2.6 million |
| "Only Safe Sap" Approach (using barriers) | $55,000 | 381 villages | Safe sap consumption option; maintained cultural practice with reduced risk | ~$3.5 million |
| TV Public Service Announcements Only | Low cost component | Broad regional coverage | Effective awareness building with lower penetration | ~$26,000 |
| Poster-Based Campaign | Moderate cost component | Village-level penetration | Supplemental reinforcement of key messages | ~$96,000 |
For researchers implementing similar interventions, the following methodological protocol provides a framework for effective communication:
Community Engagement Protocol
Qualitative Data Collection (5-7 days)
Message Co-Development (2-3 days)
Interactive Dissemination (Ongoing during outbreak)
Effective NiV management requires simultaneous attention to multiple interconnected domains:
Human Health Domain
Animal Health Domain
Environmental Health Domain
A systematic review of zoonotic risk studies found limited integration of One Health principles [89]:
These findings highlight critical disciplinary siloes that must be addressed through more transdisciplinary research approaches and participatory methodologies.
The following diagram illustrates the integrated framework for effective Nipah virus risk communication within a One Health context:
Table: Essential Research Resources for Nipah Virus Investigations
| Resource Category | Specific Tools/Reagents | Research Application | Technical Specifications |
|---|---|---|---|
| Viral Detection | qRT-PCR assays | Diagnostic confirmation of NiV infection | Targets NiV RNA; used during Kerala outbreak with 23 confirmed cases [101] |
| Computational Screening | Molecular docking simulations | Drug repurposing against Ephrin-B2 receptor | Screened 4,344 FDA-approved drugs; identified Guamecycline and Ergotamine as candidates [104] |
| Animal Models | African green monkeys, Golden hamsters | Pathogenesis and therapeutic testing | African green monkeys closely mimic human respiratory and neurological symptoms [101] |
| Serological Assays | ELISA-based antibody detection | Serosurveillance and exposure studies | Multiple formats developed for different host species [103] |
| Vaccine Platform | ChAdOx1 viral vector | Vaccine development | Same platform as AstraZeneca COVID-19 vaccine; 100,000-dose reserve established [105] |
| Behavioral Research | Structured surveys, Interview guides | Intervention effectiveness measurement | Validated instruments for knowledge, attitudes, and practice assessment [102] [106] |
The documented failures and subsequent successes in NiV outbreak communication provide critical lessons for managing emerging zoonotic diseases. The transition from ineffective one-way messaging to culturally engaged dialogue demonstrates the fundamental importance of community trust and participatory approaches. Future research must address several priority areas:
First, operationalizing the One Health framework requires genuine transdisciplinary collaboration beyond current siloes, particularly through greater inclusion of social sciences and environmental health expertise [89]. Second, therapeutic development must advance through both novel compound discovery and strategic repurposing of existing drugs [104]. The establishment of a 100,000-dose vaccine reserve represents significant progress, though alternative licensure pathways will be necessary given the challenges of conducting large-scale efficacy trials for a low-incidence, high-fatality pathogen [105].
Finally, sustained community engagement between outbreaks is essential for building the trust necessary for effective emergency response. Integrating these complementary strategies within a comprehensive One Health framework offers the most promising approach for reducing the significant global health threat posed by Nipah virus and other emerging zoonoses.
The One Health (OH) approach, which integrates human, animal, and environmental health, is increasingly recognized as essential for addressing complex health challenges, particularly wildlife parasitic zoonoses. These diseases, transmitted naturally between wildlife and humans, present unique challenges due to their complex ecology and the involvement of wildlife reservoirs. However, a significant research gap exists in the systematic validation of OH program effectiveness. A comprehensive literature review revealed that despite the proliferation of OH initiatives, standardized evaluations are generally lacking. Of 1,839 unique OH papers identified, only seven (less than 1%) reported quantitative outcomes, and these assessments did not follow a shared methodology [107]. This absence of a standardized validation framework hinders the demonstration of OH value, comparison across programs, and ultimately, the wider adoption of the approach among stakeholders and policymakers [107].
For researchers and drug development professionals focusing on wildlife parasitic zoonoses, robust validation frameworks are not merely academic exercises; they are critical tools for identifying intervention points, allocating resources efficiently, and demonstrating the impact of integrated interventions. This guide provides a technical roadmap for developing and implementing such frameworks, with specific application to parasitic zoonosis research.
Evaluating One Health initiatives requires moving beyond siloed metrics to integrated frameworks that capture interactions and outcomes across the human-animal-environment interface. The social-ecological systems (SES) framework is particularly valuable for this purpose, as it emphasizes the interactions between actors and ecological systems mediated by governing arrangements [108]. In the context of zoonoses, SES allows for the identification of different scales (international, national, local), sectors (human health, animal health, agriculture, environment), and disciplines that form the micro and macro elements of disease transmission and mitigation systems [108].
Complementing this, the Institutional Analysis and Development (IAD) framework provides a structured guideline for policy analysis. It encourages input from multiple disciplines and sectors in policy design to understand the use of information and incentives for policy adoption, and to assess how policies fit a particular context [108]. This is especially relevant for parasitic zoonoses management, where "rules-in-use" â the formal and informal rules that affect behavior â can significantly impact the success of control programs. For example, research on cysticercosis control in Peru found that hierarchical norms and unclear rules for zoonosis management between animal and environmental systems were significant barriers to effective multisectoral work [108].
Table 1: Key Theoretical Frameworks for One Health Validation
| Framework | Core Principle | Application to Wildlife Parasitic Zoonoses |
|---|---|---|
| Social-Ecological Systems (SES) | Views systems as complex, integrated entities where social and ecological components interact. | Models the interplay between wildlife habitats, human land use, parasite life cycles, and public health outcomes. |
| Institutional Analysis and Development (IAD) | Focuses on the rules, norms, and strategies that guide decision-making within organizations. | Analyzes policy barriers and enablers for multisectoral collaboration in zoonosis control. |
| One Health Systems Approach | Integrates human, animal, and environmental health through a holistic, multi-disciplinary lens. | Provides the overarching structure for designing surveillance, intervention, and evaluation strategies. |
A comprehensive validation framework for OH programs must encompass a suite of standardized indicators that capture inputs, processes, outputs, outcomes, and impacts across the three domains. Based on empirical assessments and literature, these can be categorized into several core components.
A cross-sectional study of OH platforms in Guinea, which evaluated performance across eight administrative regions, utilized a structured set of indicators that provide a practical model for assessment [5]. The overall OH performance score in Guinea was 41%, indicating a limited level of implementation, with no region reaching the 60% performance threshold [5]. This highlights the critical need for such metrics to identify weaknesses.
Table 2: Core Performance Indicators for One Health Platforms [5]
| Component | Description | Example Metrics |
|---|---|---|
| Coordination (CID) | Existence of formal intersectoral mechanisms for consultation, planning, and monitoring. | Presence of a multisectoral technical coordination committee; frequency of meetings. |
| Legislation (LID) | Existence of regulatory texts or manuals defining mechanisms for integrated disease surveillance. | Adoption of national OH policy; formalized data-sharing agreements between sectors. |
| Epidemic Detection & Documentation (EDEIPD) | Presence of documentation and early warning mechanisms for epidemic outbreaks. | Number of joint outbreak investigations; time from detection to alert. |
| Preparedness & Response (PREID) | Existence of mechanisms for epidemic preparedness and response. | Presence of a joint response plan; simulation exercises conducted. |
| Training of Actors (FPID) | Existence of training programs for personnel involved in OH platform activities. | Number of staff trained in OH principles; proportion of sectors represented. |
| Material Resources (RMID) | Availability of essential equipment for surveillance and response. | Availability of computers, vehicles, sampling kits, and diagnostic tools. |
| Funding (FID) | Presence of a dedicated budget line for the OH platform. | Consistency of funding; diversity of funding sources. |
The evaluation in Guinea revealed significant heterogeneity across regions. For instance, while the Conakry region demonstrated strong performance in legislation (89%), all regions exhibited weak capacities in the mobilization of material resources (9%), highlighting a major cross-cutting challenge [5]. This granular analysis is vital for targeting investments and support.
Beyond structural indicators, validating effectiveness requires capturing quantitative outcome metrics. These should include data from economic, epidemiological, and social assessments [107].
Diagram 1: OH Validation Workflow
The OH approach necessitates mixed-methodologies and innovative study designs. Research should combine qualitative and quantitative dataâincluding human health surveys, environmental samples, animal behavior observations, and policy analyses [109].
Data may come from existing databases (e.g., government health repositories, agricultural records, ecological datasets) or from new, primary data collection efforts [109]. Geo-coded data, such as the Gridded Livestock of the World database, are particularly valuable for spatial analyses.
Due to the multi-source and mixed-methodology nature of OH data, analytical methods must accommodate complex data structures and relationships.
Diagram 2: OH Data Integration
Implementing a OH validation framework, particularly for field-based research on parasitic zoonoses, requires a suite of essential materials and reagents. The following table details key components.
Table 3: Essential Research Reagents and Materials for OH Zoonoses Research
| Item | Function/Application | Technical Specification Notes |
|---|---|---|
| Multisectoral Data Sharing Protocols | Formal agreements enabling integration of human, animal, and environmental data. | Must address data privacy, ownership, and standardization. Critical for coordination. |
| Standardized Diagnostic Assays | Detect and confirm parasitic infections across host species (human, wildlife, domestic animals). | Requires validation for multiple species. CRISPR-based and multiplex serological assays are advancing. |
| Environmental DNA (eDNA) Sampling Kits | Collect and preserve water, soil, or fecal samples from wildlife habitats for pathogen detection. | Allows for non-invasive surveillance of parasite presence and distribution in the environment. |
| Geographic Information System (GIS) Software | Map and analyze spatial-temporal patterns of disease risk, integrating ecological and human variables. | Essential for identifying environmental drivers and high-risk hotspots for intervention. |
| Structured Interview Guides | Conduct qualitative assessments with communities and stakeholders on knowledge, attitudes, and practices. | Informs social acceptance metrics and identifies potential barriers to intervention adoption. |
| One Health Performance Assessment Tool | Systematically score OH platform functionality (e.g., Africa CDC tool). | Evaluates core components like coordination, legislation, and resources with a standardized metric [5]. |
The development and implementation of standardized validation frameworks are paramount for advancing the science of One Health and effectively managing wildlife parasitic zoonoses. By adopting the structured indicators, methodological protocols, and analytical techniques outlined in this guide, researchers and drug development professionals can generate robust, comparable evidence of what works, for whom, and under what conditions. This evidence base is critical for optimizing resource allocation, guiding policy decisions, and ultimately demonstrating the tangible value of integrated approaches to funders and policymakers. Future efforts should focus on the harmonization of these metrics across more studies and the continued development of accessible tools that lower the barrier to rigorous OH evaluation, especially in low-resource settings where the burden of parasitic zoonoses is often highest.
The One Health approach provides an essential, transdisciplinary framework for addressing the complex challenges of wildlife parasitic zoonoses. Success requires integrating surveillance across human, animal, and environmental sectors, developing innovative therapeutic and diagnostic tools, and breaking down traditional silos between disciplines. Future directions must prioritize climate-resilient strategies, equitable resource distribution, and the development of broad-spectrum interventions that account for ecological complexity. For researchers and drug developers, this means embracing systems-based approaches that consider parasite transmission networks, host-microbiome interactions, and environmental determinants of disease. The growing threats of climate change, habitat fragmentation, and global connectivity make this integrated approach not just beneficial but necessary for pandemic prevention and sustainable ecosystem health management.