Characterization of a novel Negevirus and a novel Bunyavirus isolated from Culex (Culex) declarator mosquitoes in Trinidad

Pools of mosquitoes were tested for insect-specific viruses using cytopathic effect (CPE) assays on Aedes albopictus (C6/36) cells. Illumina sequencing of RNA from pool TR7094, which produced extensive CPE 2 days post-infection, yielded the complete genome sequences of a previously unknown Bunyavirus, designated Cumuto virus (CUMV), and a second virus designated Wallerfield virus (WALV). WALV shared highest amino acid identity (60.1%) with Dezidougou virus from Côte d'Ivoire, a positive-sense, single-strand RNA, insect-specific virus belonging to the newly proposed genus Negevirus associated with mosquitoes and phlebotomine sandflies. The S, M and L segments of CUMV were most closely related to those of Gouleako virus, also from Côte d'Ivoire (amino acid identities of 36 %, 38% and 54% respectively). Neither virus produced CPE on vertebrate cells, or illness in newborn mice. Isolation and characterization of these viruses increase our knowledge of the geographical distribution, diversity and host range ofmosquito-specific bunyaviruses and negeviruses.