Dados do Trabalho

Título

Yellow fever virus in Haemagogus mosquitoes captured in an Amazonian rainforest reserve bordering Manaus, Brazil.

Introdução

Yellow fever virus (YFV) is a mosquito-borne flavivirus currently maintained in sylvatic cycles between primates as vertebrate hosts and canopy-dwelling mosquitoes (Haemagogus spp. and Sabethes spp.) as vectors in South America. Since sylvatic cycles are not amenable to human intervention and eradication, surveillance studies are crucial in identifying risk areas for virus spillover.  

Objetivo (s)

In this study, we investigated YFV in its urban and sylvatic vectors collected in the Brazilian Amazon Forest. 

Material e Métodos

From May 2021 to February 2022, mosquito collections were carried out in the Adolpho Ducke Forest Reserve, located on the border of Manaus, Amazonas, Brazil. A total of 378 pools of Haemagogus spp., 124 pools of Sabethes spp., and 122 pools of Aedes spp. were macerated and subjected to RNA extraction, followed by RT-qPCR for YFV. 

Resultados e Conclusão

Two samples of individuals Hg. janthinomys, collected in June 2022 at ground level, and one sample of an individual Hg. baresi, collected in May 2022 at ground level, tested positive for the virus. We sequenced a YFV complete genome from the RNA from Hg. janthinomys and NS1 partial fragments from Hg. janthinomys and Hg. baresi. All sequences belong to the South American I (SAI) genotype within the 1E lineage. Phylogenetic analysis of the whole genome placed the sequence in a basal position within this lineage, closely related to the sequences from the Midwest regions, not clustering within the clades of the recent YF outbreaks (2016–2021). The results confirmed the circulation of YFV in sylvatic mosquitoes, emphasizing the critical role of the Amazon Basin in the maintenance and dissemination of YFV to other regions of Brazil and neighboring countries. Additionally, we obtained the first detection of the virus in Hg. baresi, a species identified in Manaus in 1961 and the first YFV complete genome from Hg. janthionomys from Amazonas, a hotspot for arbovirus circulation. We stress that entomo-virological surveillance can provide an early warning for virus circulation and allow information to public health authorities to direct prevention/control to mitigate future outbreaks.      

Palavras Chave

Keywords: sylvatic vectors; entomological surveillance; Outbreak; Amazon basin; arboviruses.