Residual malaria of Atlantic Forest systems and the influence of anopheline fauna.

Abstract

In Brazil, the Amazon region comprises 99.5% of the reported malaria cases. However, another hotspot of the disease is the Atlantic Forest regions, with the sporadic occurrence of autochthonous human cases. In such context, this study sought to investigate the role of anopheline mosquitoes (Diptera: Culicidae) in the residual malaria transmission in Atlantic Forest areas. Two rural areas in the Espírito Santo state were the surveyed sites. Mosquitoes were captured using Shannon trap and CDC light traps and identified into species based on morphological characters. Ecological indexes (Shannon-Wiener diversity, Simpson's dominance, Pielou equability, and Sorensen similarity) were the tools used in the anopheline fauna characterization and comparison along with the two explored areas. The assessment of the sampling adequacy in the studied areas was possible through the generation of a species accumulation curve. A correlation test verified the influence of climatic variables on the anopheline species abundance. A total of 1471 female anopheline mosquitoes were collected from May 2019 to April 2020, representing 13 species. The species richness was higher in Valsugana Velha (hypo-endemic) than in Alto Caparaó (non-endemic). There was a significant variation in the species abundance between Valsugana Velha (n = 1438) and Alto Caparaó (n = 33). The most abundant species was Anopheles (Kerteszia) cruzii complex Dyar and Knab, 1908 representing 87% of the total anophelines collected. These results suggest that the Plasmodium spp. circulation in Brazilian Atlantic Forest areas occurs mainly due to the high frequency of Anopheles (K.) cruzii complex, considered the principal vector of simian and human malaria in the region.