Blood-feeding Patterns of Amazonian Forest Edge Mosquitoes

Mosquitoes are key arbovirus vectors and understanding their blood-feeding habits is crucial to elucidate potential pathogen transmission dynamics. Forest edge habitats, where natural and human-modified environments intersect, can enhance interactions among humans, wildlife, and mosquitoes, potentially enabling viral spillover and spillback. Characterizing these interactions is essential for assessing public health risks associated with diseases and guiding targeted vector management strategies.

Female mosquitoes were collected across forest edge habitats in the Adolpho Ducke forest reserve, Manaus, Brazil, using hand nets, between May 2021 and June 2022. Specimens were morphologically identified, and observable blood-engorged females were selected for blood meal analysis. DNA was extracted, and the mitochondrial cytochrome c oxidase subunit I (COI) gene was amplified and sequenced using next-generation sequencing (NGS).

A total of 141 engorged mosquitoes were selected for blood-feeding analysis, from which COI sequences were successfully obtained in 111 (78.7%) specimens. Psorophora amazonica was the predominant species (82.9%), followed by Ps. albigenu (6.3%), Haemagogus janthinomys (4.5%), and Culex coronator (1.8%). Other species, including Aedes albopictus, Hg. baresi, Ps. albipes, Ps. circumflava, and Sabethes batesi, were each represented by a single individual (0.9%). Human DNA was identified in most blood meals (88.3%), while non-human DNA included ungulates (6.3%), rodents (1.8%), non-human primates (1.8%), birds (0.9%) and carnivores (0.9%). The distribution of sampling sites showed that anthropophilic and zoophilic interactions occurred simultaneously in the same landscapes, reflecting the overlap of wild and anthropogenic habitats.

Anthropophilic mosquitoes inhabiting the edges of Amazonian forests exhibited opportunistic blood-feeding behavior, predominantly taking blood from humans but occasionally feeding on a broad diversity of non-human vertebrate hosts. This pattern is likely driven by the spatial contiguity between wild and urban/agricultural environments, which facilitates vector-mediated contact among multiple vertebrate species. These findings highlight the epidemiological relevance of forest edge habitats and reinforce the need for continuous entomological surveillance and targeted vector control strategies to mitigate the risk of arbovirus spillover and spillback.