Beneath the vibrant plumage and melodious songs of Sri Lanka's diverse bird communities lies a hidden world of conflict and survival
Across the globe, avian blood parasites silently shape bird populations, influencing their health, behavior, and evolution. In tropical Sri Lanka, where biodiversity thrives in its lush landscapes, scientists are unraveling the complex relationships between native birds, their parasitic inhabitants, and the mosquito vectors that transfer these microscopic organisms.
Sri Lanka hosts numerous endemic and migratory bird species that serve as hosts for blood parasites.
Microscopic parasites silently influence bird health and population dynamics.
Avian haemosporidian parasites are single-celled organisms that infect birds' blood cells, with three main genera causing most infections: Haemoproteus, Plasmodium, and Leucocytozoon.
Mosquito bites an infected bird, ingesting parasites with blood
Parasites undergo development within the insect vector
Infected mosquito transmits parasites to new bird host during feeding
In a comprehensive study of Sri Lankan bird communities, researchers made remarkable discoveries about the prevalence and diversity of these hidden organisms.
| Parasite Genus | Species Identified | Example Host Species |
|---|---|---|
| Haemoproteus | 4 | Yellow-browed bulbul, Oriental white-eye |
| Plasmodium | 5 | Red-vented bulbul, Asian Brown flycatcher |
The study found infections in seven different bird species, including four resident and three migratory species 2 .
No blood parasite can complete its life cycle without its insect vectors. In Sri Lanka, researchers extended their investigation beyond birds to examine potential mosquito vectors.
480 mosquito samples collected from various locations including Halgolla forest reserve and forest patches in Kurunegala and Gampola 2 .
Two mosquito species tested positive—three for Plasmodium and one for Haemoproteus 2 .
First report of Culex cinctellus in Sri Lanka, detected using bird-baited traps 8 .
Detecting these microscopic parasites requires sophisticated molecular techniques.
| Research Tool | Specific Example | Purpose in Research |
|---|---|---|
| Storage Medium | Queen's lysis buffer, 96% ethanol, filter paper | Preserves blood samples for future DNA analysis |
| DNA Extraction Kit | DNeasy Blood and Tissue Kit | Isolates genetic material from blood samples |
| Molecular Detection | Nested PCR targeting cytochrome b gene | Amplifies parasite DNA for detection |
| Morphological Identification | Microscopic examination of blood smears | Identifies parasites based on physical characteristics |
A 2023 study demonstrated that feather-based DNA could detect haemosporidian infections, offering a less invasive alternative to blood sampling 3 .
"Next-generation universal parasite diagnostics" (nUPDx) uses deep-amplicon sequencing to detect a broader range of parasites 7 .
As climate change alters temperature and precipitation patterns, the distribution of both parasites and their vectors is shifting.
Research from the Colorado Rocky Mountains has demonstrated that higher elevations, once relatively free of these parasites, are becoming more suitable for transmission as temperatures warm 6 .
In Sri Lanka, which has eliminated human malaria but remains receptive to its reintroduction through imported cases, understanding avian Plasmodium parasites provides valuable insights for public health preparedness.
The country has developed sophisticated surveillance systems, including evaluating new diagnostic technologies like the Gazelle device, which detects malaria parasites through their magnetic properties 5 .
The investigation into Sri Lanka's avian blood parasites reveals a complex web of interactions between birds, parasites, and mosquitoes. Each discovery adds another piece to the puzzle of tropical ecosystem functioning.
As research continues, scientists are increasingly recognizing how these microscopic interactions influence broader ecological patterns, potentially affecting bird population dynamics, species distributions, and community composition.