Characterization of a novel flavivirus isolated from Culex (Melanoconion) ocossa mosquitoes from Iquitos, Peru

Abstract

We describe the isolation and characterization of a novel flavivirus, isolated from a pool of Culex (Melanoconion) ocossa Dyar and Knab mosquitoes collected in 2009 in an urban area of the Amazon basin city of Iquitos, Peru. Flavivirus infection was detected by indirect immunofluorescent assay of inoculated C6/36 cells using polyclonal flavivirus antibodies (St. Louis encephalitis virus, yellow fever virus and dengue virus type 1) and confirmed by RT-PCR. Based on partial sequencing of the E and NS5 gene regions, the virus isolate was most closely related to the mosquito-borne flaviviruses but divergent from known species, with less than 45 and 71 % pairwise amino acid identity in the E and NS5 gene products, respectively. Phylogenetic analysis of E and NS5 amino acid sequences demonstrated that this flavivirus grouped with mosquito-borne flaviviruses, forming a clade with Nounané virus (NOUV). Like NOUV, no replication was detected in a variety of mammalian cells (Vero-76, Vero-E6, BHK, LLCMK, MDCK, A549 and RD) or in intracerebrally inoculated newborn mice. We tentatively designate this genetically distinct flavivirus as representing a novel species, Nanay virus, after the river near where it was first detected.

Evolutionary and phenotypic analysis of live virus isolates suggests arthropod origin of a pathogenic RNA virus family

“…Classification of arthropod-specific viruses has so far relied on multiple negative in vitro and in vivo experiments, such as the absence of viral replication in cell lines derived from different vertebrate hosts (4,5,(19)(20)(21)(22)(23)(24) or replication studies in intracerebrally inoculated newborn mice (20,23,25,26). In the case of flaviviruses, in vitro replication studies of mosquitoborne, tick-borne, and insect-specific viruses, as well as vertebrate flaviviruses of the "no known-vector" group, were in agreement with the natural host range and phylogenetic grouping of these viruses, providing evidence that in vitro replication studies can be useful for host range evaluation (19).…”

Novel flaviviruses from mosquitoes: Mosquito-specific evolutionary lineages within the phylogenetic group of mosquito-borne flaviviruses

“…Recently, six novel flaviviruses isolated from mosquitoes were published and shown to be genetically related to the taxonomically recognized mosquito-borne flaviviruses (MBFVs) (Pletnev et al, 2011), namely Nounané virus (NOUV) (Junglen et al, 2009) from Côte d’Ivoire, Chaoyang virus (CHAOV) from China and South Korea (Lee et al, 2013; Wang et al, 2009), Lammi virus (LAMV) from Finland (Huhtamo et al, 2009), Marisma mosquito virus (MMV) from Spain (Vazquez et al, 2012), Nanay virus (NANV) from Peru (Evangelista et al, 2013) and Barkedji virus from Senegal and Israel (Kolodziejek et al, 2013). …”

Phylogenetic Characterization of a Novel Insect-Specific Flavivirus Detected in a <b><i>Culex </i></b>Pool, Collected from Assam, India

“…However, the phenomenon remains to be further validated since some studies report competitive suppression of human pathogenic flaviviruses by ISFs [7,11], while others report the enhancement of transmission efficiency of human pathogenic flaviviruses by ISFs [9,10]. Even though, the surveillance of known human pathogenic arboviruses has led to the discovery of several novel viruses including ISFs [3,5,6,7,8,10,28,29,32], but their significance in transmission and pathogenesis remains to be elucidated. …”

“…It demonstrated only 77% pairwise nucleotide sequence identity over the partial NS5 region with the phylogenetically closest virus (PCV), which is far less than the recommended criterion of >84% pairwise nucleotide sequence identity required to be classified as the same ‘species' as PCV [2]. Thus, considering the above criteria and with reference to recent publications based on phylogenetic analysis of partial NS5 sequences to classify novel flaviviruses [6,8,26,27,28,29], we provisionally named this sequence ‘Assam virus' (named after the state from where it was first detected) to distinguish it from viruses reported from other parts of the world.…”