Diversity of Anopheles mosquitoes from four landscapes in the highest endemic region of malaria transmission in Brazil.

Malaria transmission in South America is overwhelmingly located in the Amazon region with limited cases outside that biome. A key factor in the mitigation of malaria transmission is the determination of vector diversity and bionomics in endemic areas. Anopheles mosquitoes were collected in four different landscapes of Cruzeiro do Sul-Acre, the current area with highest malaria transmission in Brazil. We performed adult mosquito collections every three months over two years and associated vector occurrence with local abiotic factors. A total of 1,754 Anopheles belonging to nine species were collected, but only four of them (An. albitarsis s.l. Lynch-Arribalzaga, An. braziliensis Chagas, An. peryassui Dyar and Knab, and An. triannulatus Neiva and Pinto) represented 77.1% of the total. Vector density and diversity was uneven across field sites and collection periods. Higher Anopheles abundance (54.8%) and richness were observed in a deforested palm tree area (IFC), with An. braziliensis the most frequent mosquito (40.5%). Only 7.3% of mosquitoes were collected in the SAB village, but 66.4% of them were An. darlingi and An. oswaldoi, species often regarded as primary and secondary vectors of malaria in the Amazon region. A distinct biting preference was observed between 18:00-19:40. The distance from the nearest breeding site and minimum temperature explained 41.6% of the Anopheles community composition. Our data show that the Anopheles species composition may present great variation on a microgeographic scale.