Bionomics and malaria infection rates in anopheline species in Yanomami villages of the Brazilian Amazon Forest.

BACKGROUND: Malaria remains a major public health challenge in Brazil, particularly in the Amazon region, where over 90% of cases occur. Indigenous populations, such as the Yanomami, are disproportionately affected due to geographic isolation and environmental vulnerabilities. Despite logistical challenges in remote areas entomological surveillance is essential for developing effective, culturally sensitive and ecologically appropriate vector control strategies. METHODS: From March 2013 to March 2015, a longitudinal entomological survey was conducted in five Yanomami villages in the Marari community to study vector abundance, biting behaviour and transmission dynamics. Three mosquito collection methods were used: human-protected baited traps (MosqTent), manual Nasci aspirators and CDC light traps. Detection of malaria parasites in Anopheles was performed using molecular methods. RESULTS: A total of 1962 adult Anopheles from seven species were collected. Anopheles darlingi was the predominant species in Alapusi (87.9%), Gasolina (81.9%) and Taibrapa 1 (52.5%), while Anopheles nuneztovari s.l. was most abundant in Taibrapa 2 (80.0%). Although An. darlingi was mainly captured in peridomestic settings, it was the predominant species biting and resting indoors. Molecular analysis confirmed that An. darlingi was infected with both Plasmodium vivax and Plasmodium falciparum with infection rates up to 2.1% in Gasolina and Taibrapa 1. Nightly human biting rate (nHBR) indicated An. darlingi as the predominant vector in both peridomicile and extradomicile environments across most villages. Notably, in Taibrapa 2, An. nuneztovari s.l. exhibited the highest nHBR in the extradomestic area, with estimates of up to 359 bites per night compared to only two bites per night in the peridomestic space. Entomological inoculation rate (EIR) estimates further underscore the central role of An. darlingi in malaria transmission, as the outdoors EIR recorded in Gasolina, Taibrapa 1, and Alapusi ranged from 49.3 to 79.3. CONCLUSION: These findings highlight the need for village-specific vector control strategies that consider the nocturnal activity and infection dynamics of local Anopheles populations. Tailored interventions such as optimized use of insecticide-treated hammock nets, targeted indoor residual spraying and community led environmental management should be implemented in alignment with local transmission patterns to enhance malaria control effectiveness.