Vector Bionomics of Anopheline Fauna in Malaria Endemic Areas (Three Sentinel Sites) of Bangladesh

Abstract

Background: The three Hill Tract Districts are highly malaria transmission areas in Bangladesh and intensified coverage of LLINs to reduce the number of malaria cases. Information of the bionomics of disease vectors and biting behavior is more essential to take appropriate vector control measures. The bionomics study was carried out after approximately 10 years back (2005-2006), if there any changes in vector behavior after introducing the long lasting insecticidal nets (LLINs) in malaria endemic areas. Method: Three sites were selected based on the number of last several years reported cases and malariogenic potentials including geographical condition, altitude, latitude, presence of vectors, availability of breeding sources, favorable temperature, humidity, rainfall and other possible risk factors. Mosquitoes were collected through the human and animal landing from outdoor and indoor, Pythrum Spray sheet collection, morning resting collection form human dwelling and cattle shed. Results: Mosquitoes were collected through the hand aspirator and Pyrethrum spray sheet collection during day and night time. A total of 8078 Anopheles mosquitoes, 20 specie were collected, out of that 3858 (47.76 %) are An. vagus is the most abundant followed by An. willmori 965 (11.95), An. nigerrimus 848 (10.50%), An. kochi 734 (9.09%), An. barbirostris 444 (5.50%), An. jamesii 367 (4.54 %), An. philippinensis 182 (2.25), A subpictus 163 (2.02%), An. annularis 135 (1.67%), the most virulent vector An baimaii 72(0.89), An culicifacies 51 (0.64%), An. minimus 26 (0.32%). Conclusion: The main malaria vectors A baimaii (=dirus) has been collected from 19.18 to 02.30 hrs and the pick biting period is identified 20.30 to 21.30 hrs and 21.30 to 22.30 The early biting of the An baimai indicate its behavioural changes. A vagus prevalence was higher among the collected anopheline populations in all three places.