Diversity Of Medically Important Mosquitoes In Lentic Microhabitats Prevalent Along The Daduru Oya River, Sri Lanka

Background: Mosquitoes borne diseases have become a major health issue in Sri Lanka. Regardless of the high diversity of medically important mosquitoes, in depth studies that attempt to investigate their diversity and abundance are limited in Sri Lanka. Lentic water bodies that are largely associated with lotic aquatic systems such as rock pools, sand pools, mud pools, provide ideal breeding grounds for such mosquitoes, aggravating the risk imposed by such vectors. Therefore, the current study evaluated the diversity and abundance of medically important mosquitoes, which is of paramount importance for successful vector control programs. Methods and materials: The present study was conducted at 20 sentinel sites located in the Daduru Oya river basin located in the District of Kurunagala from November, 2018 to April, 2019. Different medically important mosquitoes present in potential lentic water habitats were collected using standard dipping and siphoning methods at monthly intervals. Collected larvae were microscopically identified using taxonomic keys. Results: A total of 158 rock pools and sand pools were monitored along the river basins. A total of 542 larvae belonging to four genera, namely, Aedes (10.68%), Anopheles (53.84%), Culex (34.33%) and Aedeomyia (1.15%) were found in the river basin. An. culicifacies (35.60%), the primary vector malaria in Sri Lanka, was the most prominent mosquito species, followed by Cu. gelidus (23.80%), a major vector of Japanese encephalitis. Cu. quinquefasciatus (9.04%), the vector of Filarisis and Cu. tritaeniorhynchus (2.76%), Cu. pseudovishnui (2.58%) and Cu. vishnui (4.42%) which are considered as major vectors of Japanese encephalitis were also found as medically important vectors. Relatively lower levels of Aedes vittatus (1.29%) and Aedeomyia catasticta (35.60%) were recorded from rock pools, which are not of any proven medical importance in Sri Lanka. The abundance of mosquito species differed significantly throughout the study period (p < 0.05 at 95% level of confidence) as suggested by the statistics of Chi square test. Conclusion: A higher abundance level of medically important vector mosquitoes were found during the study, suggesting that routine entomological surveillance is important especially since the primary vectors of malaria, Japanese encephalitis and Filarisis were recorded.