Vectorial Competence Potential of Culex Quinquefasciatus (Say, 1923) from the Amazon Region to Transmit West Nile Virus Isolated in Brazil

Abstract The West Nile virus is characterized as a neurotropic pathogen that causes the West Nile fever. It is transmitted by mosquitoes, mainly of the Culex genus. In 2018, the Evandro Chagas Institute carried out the first isolation of WNV strain from a horse brain sample and in 2021 the same institute also isolated the WNV in a pool of mosquitoes of the Culex spp. from the Carajás region (Pará). Thus, this study aimed to determine the vectorial competence of Culex quinquefasciatus from the Amazon region of Brazil for transmission the WNV Brazilian strain. Oral infection of Cx. quinquefasciatus females belonging to F1 generation was performed with infected blood with WNV. Subsequently, analysis of infection, dissemination and transmission rates was performed, as well as verification of viral titers in the samples. The study demonstrated that Cx. quinquefasciatus can act as a potential vector of WNV in Brazil, since it was found that the Brazilian strain was able to overcome the host's anatomical barriers and spread to various regions, among them in saliva, in which, despite the low viral titers identified, it had a transmission rate of 100% on the 21st day after infection.