| dc.description.abstract | Until recently, malaria was a leading cause of morbidity and mortality among people in Sri Lanka. In 2016, the WHO certified the country as “malaria free”. The identification of anopheline mosquitoes is an important aspect in malaria surveillance and control. Therefore, periodical monitoring and updating of vector abundance and trends are of paramount importance to identify the potential risk of disease transmission and to forecast the entomological risk of a disease outbreak. The objective of this study is determine the trends of vector abundance and probable risk for malaria transmission in the Mannar District of Sri Lanka and compare it with past results. Three sampling locations namely; Erukkalampeddi, Pesali and Tharapura, which were surveyed during previous investigations were selected. The larval surveys were conducted from June 2018 to December 2018 on a monthly basis selecting built wells as breeding sites at each selected locality. Collected immature stages were identified to species level using morphological keys. The results of larval surveys carried out during the years 2010-2014 (in the same locations as above) and 1923-1927 (in the Mannar district) was taken for comparison. The present study encountered four species of anophelines (An. culicifacies, An. stephensi, An. subpictus, An. varuna) from larval surveys conducted in built wells (n= 406). An. culicifacies (34.5%; n= 130) was predominant followed by An. stephensi (15.1%; n= 57). However, An. culicifacies or An. stephensi was not recorded during the surveys conducted between 2010-2014 in Mannar District whilst An. subpictus had been recorded as the most abundant (96.2%) species. Earlier during the period between 1923 – 1927, An. culificacies was recorded at the time where the country was severely affected by malaria infection. Thus, there has been a change in the vector composition and abundance observed over a period of eightyear i.e. from 2010 to 2018. The recent study demonstrates that it was mainly the deep built wells which were positive for malaria vector (57.1%; n= 24), water bodies with clear (79.1%; n= 34) and sunlit (82.6%; n= 38) conditions. The presence of larvivorous fish in the vector breeding habitats was not a considerable factor totally to suppress vector breeding since approximately half of the breeding habitats which were positive for vector observed with larvivorous fish (45.5%). The study highlights the importance of continuous entomological monitoring in order to identify alternative strategies along with the potential risk due to alteration of vector breeding sites and abundance. | |
