Blood-feeding patterns of <it>Anopheles </it>mosquitoes in a malaria-endemic area of Bangladesh

<p>Abstract</p> <p>Background</p> <p>Blood-feeding patterns of mosquitoes are crucial for incriminating malaria vectors. However, little information is available on the host preferences of <it>Anopheles </it>mosquitoes in Bangladesh. Therefore, the objective of the present study was to determine the hematophagic tendencies of the anophelines inhabiting a malaria-endemic area of Bangladesh.</p> <p>Methods</p> <p>Adult <it>Anopheles </it>mosquitoes were collected using light traps (LTs), pyrethrum spray (PS), and human bait (HB) from a malaria-endemic village (Kumari, Bandarban, Bangladesh) during the peak months of malaria transmission (August-September). Enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) were performed to identify the host blood meals of <it>Anopheles </it>mosquitoes.</p> <p>Results</p> <p>In total, 2456 female anopheline mosquitoes representing 21 species were collected from the study area. <it>Anopheles vagus </it>Doenitz (35.71%) was the dominant species followed by <it>An. philippinensis </it>Ludlow (26.67%) and <it>An. minimus </it>s.l. Theobald (5.78%). All species were collected by LTs set indoors (n = 1094), 19 species were from outdoors (n = 784), whereas, six by PS (n = 549) and four species by HB (n = 29). Anopheline species composition significantly differed between every possible combination of the three collection methods (χ²test, P < 0.001). Host blood meals were successfully detected from 1318 (53.66%) <it>Anopheles </it>samples belonging to 17 species. Values of the human blood index (HBI) of anophelines collected from indoors and outdoors were 6.96% and 11.73%, respectively. The highest values of HBI were found in <it>An. baimai </it>Baimaii (80%), followed by <it>An. minimus </it>s.l. (43.64%) and <it>An. annularis </it>Van den Wulp (37.50%). <it>Anopheles baimai </it>(<it>B_i</it>= 0.63) and <it>An. minimus </it>s.l. (<it>B_i</it>= 0.24) showed strong relative preferences (<it>B_i</it>) for humans among all hosts (human, bovine, goats/sheep, and others). <it>Anopheles annularis</it>, <it>An. maculatus </it>s.l. Theobald, and <it>An. pallidus </it>Theobald exhibited opportunistic blood-feeding behavior, in that they fed on either humans or animals, depending on whichever was accessible. The remaining 12 species preferred bovines as hosts.</p> <p>Conclusions</p> <p>The observed high anthropophilic nature of <it>An. baimai</it>, <it>An. minimus </it>s.l., and <it>An. annularis </it>revealed these species to be important malaria vectors in hilly areas of Bangladesh. Higher values of HBI in outdoor-resting mosquitoes indicated that indoor collection alone is not adequate for evaluating malaria transmission in the area.</p