Genetic diversity and classification of the outer capsid glycoprotein VP7 of porcine group B rotaviruses

Abstract

We determined the nucleotide sequences of the outer capsid glycoprotein (VP7) genes of 38 porcine group B rotaviruses (GBRs) from feces of pigs at 27 farms in Japan between 2000 and 2007. Substantial diversity among porcine GBR VP7 genes was observed, with up to 42.4% difference in nucleotides and 49.8% in amino acids. On comparison of VP7 genes, porcine GBRs were clearly distinct from the published corresponding genes from human, bovine and murine GBRs (53.7-70.8% identity in nucleotides and 45.8-73.4% identity in amino acids). Phylogenetic analysis showed that the VP7s of GBRs could be divided into five genotypes: the murine strain was genotype 1, human strains were genotype 2, bovine and some porcine strains were genotype 3, and other porcine strains belonged to genotype 4 or 5. In addition, GBR VP7s in genotypes 3 and 5 were further divided into four and five clusters, respectively. No relationship between VP7 genotype and double-stranded RNA migration patterns of porcine GBRs in polyacrylamide gel electrophoresis were observed. However, an antigen enzyme-linked immunosorbent assay using antiserum to recombinant bovine GBR VP6 did not react with fecal samples containing one cluster of genotype 5 of porcine GBRs. The abundant divergence of porcine GBR VP7 genes suggests that porcine species might be an original natural host of GBR infection and that different serotypes might exist among porcine GBRs. To our knowledge, this is the first report to describe the gene sequences and typing of porcine GBR VP7s.

Analysis of genetic diversity and molecular evolution of human group B rotaviruses based on whole genome segments

“…Animal GBRs are genetically distinct from human GBRs and contain divergent populations of viruses. According to the classification of GBR in terms of the VP7 gene by Kuga et al (2009), GBRs were divided into five genotypes (G1-G5), comprising a single genotype (G2) of human strains and the other four genotypes of murine, porcine and bovine strains. Although genetic and molecular epidemiological study of GBR has been based primarily on the VP7 gene, genetic information of other viral gene segments is extremely limited.…”

“…So far, full-genome information has been available for only a murine strain and three human strains, and eight gene segments have been sequenced for a bovine strain (Ghosh et al, 2007(Ghosh et al, , 2010. For ovine and porcine GBRs, sequence data of only a few gene segments are available (Shen et al, 1999;Kuga et al, 2009). In the present study, nearly full-length sequences of four human GBRs were determined, which enabled us to analyse substantially the genetic diversity of GBR at the fullgenome level.…”

“…Phylogenetic analysis of GBR genes encoding VP1, VP2, VP4, VP6, NSP1, NSP2 and NSP5 revealed the presence of murine, human and bovine GBR clusters corresponding to GBR genotypes G1, G2 and G3, respectively, which had been classified for the VP7 gene (Kuga et al, 2009) (Fig. 1b, c, e-h, k).…”

“…Recently, Kuga et al (2009) proposed a classification scheme for GBR genotypes in terms of VP7 gene sequence, and GBRs were divided into five genotypes (G1-G5), among which human strains were assigned to a single genotype, G2. The human GBRs detected were classified genetically into two lineages within genotype G2 based on the VP7 gene: the Chinese lineage and the Indian-Bangladeshi lineage (Ahmed et al, 2004;Yang et al, 2004;Aung et al, 2009).…”

Genetic and Histopathological Identification of <i>Cystoisospora suis</i> in a Post-weaned Piglet with Watery Diarrhea

“…On April 6, 2016, 60-day-old piglets were observed to have gray watery diarrhea, emaciation, a rough coat, labored breathing, and difficulty standing. Two pooled samples of diarrheal content (six animals/pool) were examined for group A, B and C rotavirus [GAR (Chinsangaram et al 1993), GBR (Kuga et al 2009), GCR (Tsunemitsu et al 1996], porcine epidemic diarrhea (PED) virus (Ishikawa et al 1997), and transmissible gastroenteritis (TGE) virus (Paton et al 1997) by PCR. One pooled sample tested positive for only GAR.…”