Summary

Wild birds serve as amplifying hosts for many viruses and pathogens in nature that are transmissible to humans and other wildlife. For instance, birds that migrate across national and intercontinental borders can become long range vectors that introduce many pathogens to their migratory destinations creating “emerging infectious diseases”. These pathogens have been reported to transmit from birds to humans and other mammals through the bites of bird feeding (ornithophilic) mosquitoes.

Such ornithophilic mosquitoes play a major role in the significant disease outbreaks in humans and animals in many parts of the World. Therefore broad understanding of mosquito species that feed on birds and the vector host relationships are essential for the risk assessment of emerging infectious diseases. The most important factor about these mosquitoes is that their ability to feed on diverse host range. Sri Lanka is a tropical island with a high endemism and diversity of bird fauna. The country is consider as a biodiversity hotspot with preferred ecological conditions for diverse year round migrant birds. On the other hand, the country is well known for the high diversity and abundance of mosquito fauna. The high diversity of resident and migrant bird species in the country provides excellent opportunities to explore unique relationships between avifauna and the mosquitoes that bite them. No studies, however, have been carried out in Sri Lanka to explore the bird mosquito interactions, the potential avian vector borne diseases and the risk assessment of emerging infectious diseases that can be introduce through bird-mosquito interactions. Therefore the present study proposes to determine the abundance, distribution and diversity of Sri Lankan ornithophilic mosquitoes and their role as potential vectors of disease causing pathogens to local bird populations to and other mammals.

In implementing the study, mosquito sampling will be carried out in study sites with high abundance and endemism of bird fauna as well as migratory birds, covering the wet and dry zones of the country over a period of 24 months. The observations of biting behavior, field sampling and collection of mosquitoes, blood samples and ecological data will be done monthly in each study site. Bird blood samples will be analyzed using molecular tools and blood smear analysis to report the presence of blood parasites and the abundance of pathogens in bird blood. Blood fed mosquitoes will be analyzed by the real time PCR to determine the host blood type. The presence of pathogens in the mosquito body will be determined by analyzing the thoracic and abdominal parts of collected mosquitoes via molecular analysis and microscopic slides.

The results of this study will provide new information about the mosquitoes that specialized on feeding bird blood and the possible zoonotic diseases that can swing from birds to mammals via more generalist feeding bird-biting mosquitoes. More importantly, the outcomes of vector-host relationships of bird-biting mosquitoes will provide useful information about the future risks of epidemics. Better understandings of such relationships are important in exploring the possible zoonotic diseases that are transmitted by bird biting mosquitoes to humans and the wildlife in Sri Lanka. The findings of the study will, therefore, open new research pathways to carry out more exciting studies about bird enzootic diseases that can be transferred to humans. The study will ultimately contribute to the risk assessment programs and predictions of future outbreaks of mosquito borne diseases in the country.

Objectives

To investigate the diversity, distribution, abundance and the biting behavior of Ornithophilic mosquitoes and their potential role as vectors of zoonotic diseases.

1. To report the presence of ornithophilic mosquitoes in Sri Lanka.

2. To determine the species composition, distribution and the abundance of ornithophilic mosquito species in the wet and the dry zones of Sri Lanka.

3. To investigate the biting behavior of these mosquitoes.

4. To determine the pathogens presence in the blood of the local bird populations and mosquitoes that bites them (determine the role in the transmission of zoonotic pathogens to multiple host communities).

5. To determine the mosquito species that interacts with migratory birds of Sri Lanka.

6. To report the pathogens presence in the blood of the migratory birds of Sri Lanka