Description of malaria vectors (Diptera: Culicidae) in two agricultural settlements in the Western Brazilian Amazon

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Alice Oliveira Andrade, Najara Akira Costa dos Santos, Raphael Brum Castro, Isabelle Sousa de Araujo, Alessandra da Silva Bastos, Felipe Neves Magi, Moreno Magalhães de Souza Rodrigues, Dhélio Batista Pereira, Jansen Fernandes Medeiros, Maisa da Silva Araújo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 2021
• Subjects: Anopheles; Disease transmission; Rural communities; Brazil; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/s1678-9946202163060; https://doaj.org/article/6b4524941bc44255b8c5d50c17841945

ABSTRACT The majority of malaria cases in South America occur in rural areas of the Amazon region. Although these areas have a significant impact on malaria cases, few entomological studies have been carried out there. This study aimed to describe entomological parameters in settlements in Rondonia State, Brazil. Collections of anopheles were carried out using the Protected Human Attraction Technique (PHAT). The risk and the potential for malaria transmission were assessed using the human biting rate (HBR), the sporozoite rate (SR) and the entomological inoculation rate (EIR). The results confirmed that Nyssorhynchus darlingi is the predominant species in the two studied locations. Although settlement in the two study sites has occurred at different times, the species richness found was low, showing that environmental changes caused by anthropological actions have probably favor the adaptation of Ny. darlingi species. From the total of 615 anopheline mosquitoes assessed, seven (1.1%) were positive for Plasmodium sp. infections. The EIR revealed that Ny. darlingi contributes to malaria transmission in both locations, as it was responsible for 0.05 infectious bites in humans at night in the old settlement and 0.02 in the recent occupation. In the two study sites, the biting occurred more frequently at dusk. Nyssorhynchus darlingi was prevalent in areas of recent colonization but, even when present in a low density, this species could maintain the transmission of malaria in the older settlement. The entomological information obtained in this study is important and may aid the selection of vector control actions in these locations.