A New Flavivirus and a New Vector: Characterization of a Novel Flavivirus Isolated from Uranotaenia Mosquitoes from a Tropical Rain Forest

A novel flavivirus was isolated from Uranotaenia mashonaensis, a mosquito genus not previously known to harbor flaviviruses. Mosquitoes were caught in the primary rain forest of the Tai National Park, Cote d'Ivoire. The novel virus, termed nounane virus (NOUV), seemed to grow only on C6/36 insect cells and not on vertebrate cells. Typical enveloped flavivirus-like particles of 60 to 65 nm in diameter were detected by electron microscopy in the cell culture supernatant of infected cells. The full genome was sequenced, and potential cleavage and glycosylation sites and cysteine residues were identified, suggesting that the processing of the NOUV polyprotein is similar to that of other flaviviruses. Phylogenetic analyses of the whole polyprotein and the NS3 protein showed that the virus forms a distinct cluster within the clade of mosquito-borne flaviviruses. Only a distant relationship to other known flaviviruses was found, indicating that NOUV is a novel lineage within the Flaviviridae.