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


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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    • "Similarly, the second, third and fourth unique groups of viruses, also initially identified from the cohort of mosquitoes collected in Cote d'Ivoire, do not replicate in vertebrate cells and phylogenetically could not be assigned to an established bunyavirus genus (Marklewitz et al., 2015, 2013). Viruses that appear only to replicate in a mosquito vector, without the requirement for vertebrates as part of their transmission cycle, have also been identified in other arbovirus families (Cook et al., 2006; Crabtree et al., 2003; Hoshino et al., 2007; Nasar et al., 2012). Recent analysis of these viruses is providing valuable information on the evolution and genetic divergence of individual viral species, and molecular determinants of transmissibility and pathogenesis. "
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    ABSTRACT: Insect-specific viruses belonging to significant arboviral families have recently been discovered. These viruses appear to be maintained within the insect population without the requirement for replication in a vertebrate host. Mosquitoes collected from Badu Island in the Torres Strait in 2003 were analysed for insect-specific viruses. A novel bunyavirus was isolated in high prevalence from Culex spp. The new virus, provisionally called Badu virus (BADUV), replicated in mosquito cells of both Culex and Aedes origin, but failed to replicate in vertebrate cells. Genomic sequencing revealed that the virus was distinct from sequenced bunyavirus isolates reported to date, but phylogenetically clustered most closely with recently discovered mosquito-borne, insect-specific bunyaviruses in the newly proposed Goukovirus genus. The detection of a functional furin cleavage motif upstream of the two glycoproteins in the M segment-encoded polyprotein suggests that BADUV may employ a unique strategy to process the virion glycoproteins.
    No preview · Article · Feb 2016 · Virology
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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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    ABSTRACT: Several flaviviruses are important pathogens for humans and animals (Dengue viruses, Japanese encephalitis virus, Yellow-fever virus, Tick-borne encephalitis virus, West Nile virus). In recent years, numerous novel and related flaviviruses without known pathogenic capacity have been isolated worldwide in the natural mosquito population. However, phylogenetic studies have shown that genomic sequences of these viruses diverge from other flaviviruses. Moreover, these viruses seem to be exclusive of insects (they do not seem to grow on vertebrate cell lines), and were already defined as mosquito-only flaviviruses or insect-specific flaviviruses. At least eleven of these viruses were isolated worldwide, and sequences ascribable to other eleven putative viruses were detected in several mosquito species. A large part of the cycle of these viruses is not well known, and their persistence in the environment is poorly understood. These viruses are detected in a wide variety of distinct mosquito species and also in sandflies and chironomids worldwide; a single virus, or the genetic material ascribable to a virus, was detected in several mosquito species in different countries, often in different continents. Furthermore, some of these viruses are carried by invasive mosquitoes, and do not seem to have a depressive action on their fitness.
    Full-text · Article · Jul 2015 · Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases
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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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    ABSTRACT: Novel flaviviruses that are genetically related to pathogenic mosquito-borne flaviviruses (MBFV) have been isolated from mosquitoes in various geographical locations, including Finland. We isolated and characterized another novel virus of this group from Finnish mosquitoes collected in 2007, designated as Ilomantsi virus (ILOV). Unlike the MBFV that infect both vertebrates and mosquitoes, the MBFV-related viruses appear to be specific to mosquitoes similar to the insect-specific flaviviruses (ISFs). In this overview of MBFV-related viruses we conclude that they differ from the ISFs genetically and antigenically. Phylogenetic analyses separated the MBFV-related viruses isolated in Africa, the Middle East and South America from those isolated in Europe and Asia. Serological cross-reactions of MBFV-related viruses with other flaviviruses and their potential for vector-borne transmission require further characterization. The divergent MBFV-related viruses are probably significantly under sampled to date and provide new information on the variety, properties and evolution of vector-borne flaviviruses.
    Full-text · Article · Sep 2014 · Virology
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