Molecular analysis of the S glycoprotein gene of bovine coronaviruses isolated in Japan from 1999 to 2006

In total, 55 isolates of Bovine coronavirus (BCoV) were collected from cases of enteric and respiratory disease occurring between 1999 and 2006 in Japan. Phylogenetic analysis of the polymorphic region of the S glycoprotein gene of these isolates, together with those of other known strains, classified the BCoV strains and isolates into four clusters. Recent field isolates display distinctive genetic divergence from the prototype enteric BCoV strains--Mebus, Quebec, Kakegawa, F15 and LY138--and have diverged in three different aspects over 8 years. These data suggested that the genetic divergence in the polymorphic region of the S glycoprotein has progressed considerably; thus, molecular analysis of this region should be useful in investigating the molecular epidemiology of BCoV. In addition, based on the differences in amino acids among the isolates, our study did not reveal the presence of certain genetic markers of pathogenicity and clinical symptoms in this polymorphic region.