Publications (3)3.12 Total impact
Article: No apparent difference in the prevalence of parvovirus B19 infection between chronic fatigue syndrome patients and healthy controls in Japan.Journal of clinical virology: the official publication of the Pan American Society for Clinical Virology 03/2009; 44(3):246-7. · 3.12 Impact Factor
Article: Full-Length Sequences of One Genotype 4 and Three Genotype 3 Hepatitis E Viruses in Fecal Samples from Domestic Swine in Japan[show abstract] [hide abstract]
ABSTRACT: The Hepatitis E virus (HEV) induces zoonotic infections and causes hepatitis. In Japan, HEV occurs in deer, wild boar and swine, and genotype (G)3 and G4 have been isolated from domestic swine. We previously reported that HEV isolates from a total of 320 swine fecal samples from 32 farms in Japan could be predominantly classified into four clusters: three G3 (G3 JP , G3 SP and G3 US) and one G4 (G4 JP). In this study, we performed full-length sequencing of four representative HEVs, one from each of the clusters. We found significant nucleotide variation throughout the sequences within a genotype, but not within each cluster. However, we found few variations at the amino acid level. Most of the highly conserved regions within genotypes were concentrated in the overlapping region of open reading frame (ORF)2 and ORF3, while most of the variable regions were within the ORF1 V region. This region was variable even at the amino acid level. Essentially, this region was highly conserved among G3 clusters, with some more dissimilarities between G3 SP and the other two clusters, G3 JP and G3 US . The regions conserved and variable across genotypes had virtually the same positions as those within genotypes, but were much narrower and wider, respectively. For the latter, ORF1 V and P regions were especially variable. Finally, we focused on the sequence conservation in the region widely used for primer and probe sets to detect HEV infections.
Article: Sequence variation in hepatitis E virus genotypes 3 and 4 from swine fecal samples in Japan[show abstract] [hide abstract]
ABSTRACT: Hepatitis E virus (HEV) is a causative agent for hepatitis. HEV is transmitted via the fecal-oral route through contaminated drinking water and induces zoonotic infections through eating uncooked and undercooked meat of deer, wild boar, and swine. In Japan, genotypes 3 (G3) and 4 (G4) are prevalent in domestic swine. Here, we examined the genetic variation among HEVs derived from swine fecal samples in Japan. A total of 320 samples were collected at 32 commercial farm facilities (1 fecal sample from each of 10 pig houses in individual farms). Viral RNA amplification at open reading frame (ORF) 3 was possible in 159 (49.7%) of the fecal samples. For genotyping, the same samples were subjected to amplification at ORF2 and the resulting amplicons were sequenced. The results revealed that all the HEVs in each farm belonged to the same cluster of G3 and G4: G3 JP in 8 farms, G3 SP in 4 farms, G3 US in 6 farms, and G4 JP in 2 farms, unclassified G3 in 2 farms, unable to decide due to a low rate of amplification in 5 farms, and no detection in 5 farms. Interestingly, the HEVs from one farm were more homogeneous than those of the same cluster that was derived from other farms. Thus, the efficiency of farm-to-farm transmission of HEVs is likely to be low and HEV seems to have evolved independently at each farm in Japan.