Nhumirim virus, a novel flavivirus isolated from mosquitoes from the Pantanal, Brazil

We describe the isolation of a novel flavivirus, isolated from a pool of mosquitoes identified as Culex (Culex) chidesteri collected in 2010 in the Pantanal region of west-central Brazil. The virus is herein designated Nhumirim virus (NHUV) after the name of the ranch from which the mosquito pool was collected. Flavivirus RNA was detected by real-time RT-PCR of homogenized mosquitoes and from the corresponding C6/36 culture supernatant. Based on full-genome sequencing, the virus isolate was genetically distinct from but most closely related to Barkedji virus (BJV), a newly described flavivirus from Senegal. Phylogenetic analysis demonstrated that NHUV grouped with mosquito-borne flaviviruses forming a clade with BJV. This clade may be genetically intermediate between the Culex-borne flaviviruses amplified by birds and the insect-only flaviviruses.