First study of the susceptibility of Culex quinquefasciatus from the Amazon Region to become infected and transmit the West Nile virus strain isolated in Brazil

West Nile virus is characterized as a neurotropic pathogen transmitted by Culex genus mosquitoes that cause West Nile fever. In 2018, the Evandro Chagas Institute performed the first isolation of a WNV strain in Brazil, from a horse brain sample. This study aimed to evaluate the susceptibility of Cx. quinquefasciatus from the Amazon region of Brazil to become infected and transmit the WNV strain isolated in 2018. Oral infection of naive F1 generation females was performed with sheep bloodmeal artificially infected with WNV, followed by analysis of infection, dissemination, and transmission rates, as well as viral titers of body, head, and saliva samples.  The infection rate was 100% in all dpe evaluated. The dissemination rates varied in the three dpe, with a 40%, 37.5%, and 100% in the 7th, 14th, and 21st dpe, respectively. The transmission rate was 100% from the 21st dpe. These results indicate that that Cx. quinquefasciatus is susceptible to oral infection by the Brazilian strain of WNV