Article

Genetic and phenotypic characterization of the newly described insect flavivirus, Kamiti River virus

Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Fort Collins, Colorado 80522, USA.
Archives of Virology (Impact Factor: 2.39). 07/2003; 148(6):1095-118. DOI: 10.1007/s00705-003-0019-7
Source: PubMed

ABSTRACT

We have described in the accompanying paper by Sang, et al., ([57], Arch Virol 2003, in press) the isolation and identification of a new flavivirus, Kamiti River virus (KRV), from Ae. macintoshi mosquitoes that were collected as larvae and pupae from flooded dambos in Central Province, Kenya. Among known flaviviruses, KRV was shown to be most similar to, but genetically and phenotypically distinct from, Cell fusing agent virus (CFAV). KRV was provisionally identified as an insect-only flavivirus that fails to replicate in vertebrate cells or in mice. We report here the further characterization of KRV. Growth in cell culture was compared to that of CFAV; although growth kinetics were similar, KRV did not cause the cell fusion that is characteristic of CFAV infection. The KRV genome was found to be 11,375 nucleotides in length, containing a single open reading frame encoding 10 viral proteins. Likely polyprotein cleavage sites were identified, which were most similar to those of CFAV and were comparable to those of other flaviviruses. Sequence identity with other flaviviruses was low; maximum identity was with CFAV. Possible terminal secondary structures for the 5' and 3' non-coding regions (NCR) were similar to those predicted for other flaviviruses. Whereas CFAV was isolated from insect cells in the laboratory, the isolation of KRV demonstrates the presence of an insect-only flavivirus in nature and raises questions regarding potential interactions between this virus and other mosquito-borne viruses in competent vector populations. Additionally, this virus will be an important tool in future studies to determine markers associated with flavivirus host specificity.

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    • "To date, CFAV was already isolated from natural mosquito populations in Puerto Rico (Cook et al., 2006) and Thailand (Yamanaka et al., 2013), and was also detected in field-collected mosquitoes in Mexico (Espinoza-Gómez et al., 2011), Indonesia (Hoshino et al., 2009), and Argentina (GenBank accession numbers (GB): DQ335466-7). Other viruses related to CFAV were subsequently isolated directly from field-collected mosquitoes, such as Kamiti River virus (KRV) in Kenya (Crabtree et al., 2003; Sang et al., 2003); Culex flavivirus (CxFV) in Japan, Guatemala, USA, Mexico, Uganda, Caribbean, China, Brazil, and Argentina (Hoshino et al., 2007; Morales-Betoulle et al., 2008; Blitvich et al., 2009; Bolling et al., 2011; Cook et al., 2009; Kim et al., 2009; Farfan-Ale et al., 2010; Saiyasombat et al., 2010; Huanyu et al., 2012; Chen et al., 2013; Machado et al., 2012; Goenaga et al., 2014); Aedes flavivirus (AeFV) in Japan (Hoshino et al., 2009), Italy (Roiz et al., 2012; Grisenti et al., 2015), and USA (Haddow et al., 2013); Quang Binh virus (QBV) in Vietnam (Crabtree et al., 2009); Nakiwogo virus in Uganda (Cook et al., 2009); Calbertado virus in North America (Bolling et al., 2011; Tyler et al., 2011); Hanko virus in Finland (Huhtamo et al., 2012); Culex theileri flavivirus in Portugal (Parreira et al., 2012); Palm Creek virus in Australia (Hobson-Peters et al., 2013); and Nienokoue virus in Ivory Coast (GB: JQ957875). The isolation and characterization of an ISFV, Ochlerotatus caspius flavivirus (OcFV), from Aedes caspius mosquitoes collected in southern Portugal and closely related to the Hanko virus was recently reported (Ferreira et al., 2013). "
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    • "Additionally , another group of flaviviruses that has been characterized in more recent years, the insect-specific flaviviruses (ISFs) are currently known to infect only insect hosts, primarily mosquitoes. These viruses include cell fusing agent virus (CFAV) (Cammisa- Parks et al., 1992; Stollar and Thomas, 1975), Kamiti River virus (KRV) (Crabtree et al., 2003; Sang et al., 2003) and many recently identified related viruses from different regions of the world (Cook et al., 2006, 2009, 2012; Crabtree et al., 2009; Farfan-Ale et al., 2009; Hoshino et al., 2007, 2009; Huhtamo et al., 2012; Kim et al., 2009; Morales-Betoulle et al., 2008). Interestingly, some of these ISFs appear to be capable of integrating their genomic sequences into mosquito genomes (Crochu et al., 2004). "
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