Characterization of Anopheles species temporal compositions and bionomic characteristics in Bandarban, Bangladesh

This study sought to characterize temporal and spatial Anopheles species compositions and behaviors throughout the rainy season towards understanding present gaps in transmission that result in residual malaria transmission.



Anopheles mosquitoes were sampled from four villages in malaria-endemic Bandarban district, Bangladesh, from May through October, 2018. Sampling methods used included CDC-Light traps (CDC-LT), human landing catches (HLC), and pyrethrum spray catches (PSC). Species identification of female specimens was conducted both morphologically as well as molecularly - using ITS2 and CO1 sequences.



A total of 5376 Anopheles specimens were collected belonging to 17 species – An. vagus was the dominant species (39.7%) followed by An. nivipes (12.5%). The months following peak rainfall in June had the highest Anopheles biomass. Outdoor catches were usually higher than indoor catches at all four sites. A large variation in species-specific biting behaviors demonstrates a complex vector ecology with An. vagus demonstrated the highest endophily (95% of indoor resting mosquitoes) as well as the highest anthropophagy.



This study points to the primary vector at these sites being An. vagus. Gaps in protection with indoor-based interventions include vectors and humans overlapping in the early evening and outdoors where interventions are absent. Targeting An. vagus indoor resting behavior with non-pyrethroid-based indoor residual spraying (IRS) may be effective against this vector. Other interventions targeting transmission that occurs outside the scope of LLINs and IRS are required with malaria elimination being the goal.