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Group C rotavirus (GCRV) is distributed worldwide as an enteric pathogen in humans and animals. However, to date, whole-genome sequences are available only for a human strain (Bristol) and a porcine strain (Cowden). To investigate the genetic diversity of human GCRVs, nearly full-length sequences of all 11 RNA segments were determined for human GCRVs detected recently in India (v508), Bangladesh (BS347), China (Wu82 and YNR001) and Japan (OH567 and BK0830) and analysed phylogenetically with sequence data for GCRVs published previously. All the RNA segments of human GCRV strains except for the VP3 gene showed high levels of conservation (.93 % nucleotide sequence identity, .92 % amino acid sequence identity), belonging to a single genetic cluster distinct from those of animal GCRVs. In contrast, the VP3 genes of human GCRVs could be discriminated into two clusters, designated M2 and M3, that were distinguished phylogenetically from those of porcine and bovine GCRVs (clusters M1 and M4, respectively). Between M2 and M3, amino acid sequence identity of the VP3 gene was 84.1-84.7 %, whereas high identities were observed within each cluster (92.3-97.6 % for M2, 98.2-99.3 % for M3). Sequence divergence among the four VP3 clusters was observed throughout the amino acid sequence except for conserved motifs, including those possibly related to enzyme functions of VP3. The presence of obvious genetic diversity only in the VP3 gene among human GCRVs suggested that either the M2 or M3 VP3 gene of human GCRVs might have been derived through reassortment from an animal GCRV or from an unidentified human GCRV strain belonging to a novel genogroup. INTRODUCTIONRotavirus, a member of the family Reoviridae, is the most important viral pathogen that causes gastroenteritis in humans. The rotavirus genome consists of 11 segments of dsRNA, and the viral particle is composed of three concentric layers, the outer capsid, inner capsid and core (Estes & Kapikian, 2007). The outer capsid consists of two structural proteins, VP4 and VP7, which contain neutralization antigens. The inner capsid consists of structural protein VP6. Rotavirus is classified into seven groups, A-G, based on the antigenicity of the inner capsid protein VP6 and genomic characteristics (Kapikian et al., 2001). In humans, groups A, B and C have been detected to date. Group A rotavirus (GARV) is the most prevalent throughout the world and is recognized as the leading viral pathogen of acute gastroenteritis in children. For epidemiological investigations of GARV, a genetic classification system based on the outer capsid proteins VP7 (G type) and VP4 (P type) has been adopted (Santos & Hoshino, 2005). In addition, a full-genome-based genotyping system composed of genotypes of the 11 individual RNA segments has been proposed on the basis of full-The GenBank/EMBL/DDBJ accession numbers for the GCRV sequences determined in this study are HQ185629-HQ185631 (v508), HQ185632-HQ185642 (BS347), HQ185643-HQ185651 (Wu82), HQ185652-HQ185662 (YNR001), HQ185663-HQ185672 (OH567) and ...

This study reports the first complete genome sequence of a caprine group A rotavirus (GAR) strain, GO34. The VP7-VP4-VP6-VP1-VP2-VP3-NSP1-NSP2-NSP3-NSP4-NSP5 genes of strain GO34, detected in Bangladesh, were assigned to the G6-P[1]-I2-R2-C2-M2-A11-N2-T6-E2-H3 genotypes, respectively. Strain GO34 was closely related to the VP4, VP6-7 and NSP4-5 genes of bovine GARs and the NSP1 gene of GO34 to an ovine GAR. Strain GO34 shared low nucleotide sequence identities (,90 %) with VP2-3 genes of other GARs, and was equally related to NSP3 genes of human, ruminant and camelid strains. The VP1, VP6 and NSP2 genes of strain GO34 also exhibited a close genetic relatedness to human G2, G6, G8 and G12 DS-1-like GARs, whereas the NSP1 of GO34 was also closely related to human G6P [14] strains. All these findings point to a common evolutionary origin of GO34 and bovine, ovine, antelope, guanaco and human G6P [14] GARs, although phylogenetically GO34 is not particularly closely related to any other rotavirus strains known to date.Group A rotaviruses (GARs) are a major cause of acute viral gastroenteritis in the young of humans and animals (Estes & Kapikian, 2007). The GAR genome consists of 11 segments of double-stranded RNA, encoding six structural and six non-structural proteins (Estes & Kapikian, 2007). Recently, the 11 GAR gene segments (VP1, VP2, VP3, VP4, VP6, VP7, NSP1, NSP2, NSP3, NSP4 and NSP5 genes) have been classified into at least six R, six C, seven M, 31 P, 13 I, 23 G, 16 A, six N, eight T, 12 E and eight H genotypes, respectively, based on specific nucleotide sequence identity cut-off percentages for each gene segment (Matthijnssens et al., 2008a(Matthijnssens et al., , b, 2009(Matthijnssens et al., , 2010aSchumann et al., 2009;Solberg et al., 2009;Trojnar et al., 2009;Ursu et al., 2009). Applying this classification scheme, the full genomes of GAR strains from antelope, birds, cattle, cats, dogs, guanacos, humans, monkeys, pigs, rabbits and sheep were successfully analysed, providing vital insights into the complex genetic diversity of GARs (Ghosh et al., 2010;Heiman et al., 2008;Matthijnssens et al., 2008a Matthijnssens et al., , b, 2009Matthijnssens et al., , 2010aSchumann et al., 2009;Trojnar et al., 2009;Tsugawa & Hoshino, 2008).GARs have been associated with diarrhoea in goats from different parts of the world (Kaminjolo & Adesiyun, 1994;Lee et al., 2003;Mendes et al., 1994; Muñoz et al., 1996;Pratelli et al., 1999; Takahashi et al., 1979;Scott et al., 1978). Moreover, in rural areas, caprine GARs might pose a threat to humans living in close proximity to livestock. However, to date, few caprine GAR strains have been molecularly characterized. Among them, the VP7, VP4 and NSP4 gene sequences of a Korean caprine strain, GRV, were assigned to G3, P[3] and E3 genotypes, respectively, and this strain was believed to be derived from reassortment events and/or interspecies transmission of canine, feline and/or simian GARs (Lee et al., 2003). The fulllength VP7 and partial VP4 gene sequences (GenBank accessi...

Novel rotavirus strains B219 and ADRV-N derived from adult diarrheal cases in Bangladesh and China, respectively, are considered to belong to a novel rotavirus group (species) distinct from groups A, B, and C, by genetic analysis of five viral genes encoding VP6, VP7, NSP1, NSP2, and NSP3. In this study, the nucleotide sequences of the remaining six B219 gene segments encoding VP1, VP2, VP3, VP4, NSP4, and NSP5 were determined. The nucleotide sequences of the group B human rotavirus VP1 and VP3 genes were also determined in order to compare the whole genome of B219 with those of group A, B, and C rotavirus genomes. The nucleotide and deduced amino acid sequences of all B219 gene segments showed considerable identity to the ADRV-N (strain J19) sequences (87.7-94.3% and 88.7-98.7%, respectively). In contrast, sequence identity to groups A-C rotavirus genes was less than 61%. However, functionally important domains and structural characteristics in VP1-VP4, NSP4, and NSP5, which are conserved in group A, B, or C rotaviruses, were also found in the deduced amino acid sequences of the B219 proteins. Hence, the basic structures of all B219 viral proteins are considered to be similar to those of the known rotavirus groups.

To clarify the phylogenetic relatedness of rotaviruses causing gastroenteritis in children and adults, an epidemiologic investigation was conducted in Mymensingh, Bangladesh, during the period between July 2004 and June 2006. A total of 2,540 stool specimens from diarrheal patients from three hospitals were analyzed. Overall, rotavirus-positive rates in children and adults were 26.4 and 10.1%, respectively. Among the 155 rotavirus specimens examined genetically from both children and adults, the most frequent G genotype was G2 (detection rate: 54.0 and 47.6%, respectively), followed by G1 (21.2 and 26.2%, respectively), and G9 (15.9 and 9.5%, respectively). G12 was also detected in five specimens (3.2% in total; four children and one adult). Sequence identities of VP7 genes of G2 rotaviruses from children and adults were higher than 97.8%, while these Bangladeshi G2 viruses showed generally lower identities to G2 rotaviruses reported elsewhere in the world, except for some strains reported in African countries. Similarly, extremely high sequence identities between children and adults were observed for VP7 genes of G1, G9 and G12 rotaviruses, and also for the VP4 genes of P[4], P[6], and P[8] viruses. Rotaviruses from children and adults detected in this study were included in a single cluster in phylogenetic dendrograms of VP7 or VP4 genes of individual G/P types. Rotaviruses with two emerging types, G9 and G12, had VP7 genes that were phylogenetically close to those of individual G-types recently reported in Bangladesh and India and were included in the globally spreading lineages of these G-types. These findings suggested that genetically identical rotaviruses, including those with the emerging types G9 and G12, were circulating among children and adults in city and rural areas of Bangladesh.