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Only two strains (Shintoku and porcine-like WD534tc) of group C rotavirus (GCR) from cattle have been reported to date. A GCR designated the Yamagata strain was the only pathogen detected in an outbreak of adult cow diarrhea accompanied by a decrease in milk production. The nucleotide sequences of the VP6 and VP7 genes from strain Yamagata were determined. Comparative sequence analysis showed that the sequence identities between strains Yamagata and Shintoku were markedly high in both VP6 gene (98.1%) and VP7 gene (93.5%), and that these strains belonged to the same clusters which were distinguished from GCRs from different host species in phylogenetic trees of these genes. These results suggested strongly that cattle species is one of the natural hosts of GCR infection, and that GCRs are a cause of adult cow diarrhea.

A wasting disease characterized by progressive weight loss and dyspnea has been observed in weaning pigs on a farm in Yamagata Prefecture in 1998. Histopathologic findings in an affected pig were bronchointerstitial pneumonia and intracytoplasmic clusters of basophilic inclusions in macrophages of lymph nodes, which were similar to those in pigs with postweaning multisystemic wasting syndrome (PMWS) recently reported in North America and Europe. Porcine circovirus (PCV)-like particles were observed in bronchial lymph node of the pig by electron microscopy, and PCV antigens were detected in the lesions by immunohistochemical staining. PCV DNA was also detected in the lung and tonsil by PCR, and restriction fragment length polymorphism analysis of the PCR products with HinfI showed the same type of the PCV associated with PMWS (pmws PCV). Homology of nucleotide sequences between the PCR product and corresponding regions of published pmws PCV genomes was very high. These results indicated that virus detected in this study was pmws PCV. To our knowledge, this is the first report on the presence of pmws PCV in Japan.