Isolation of two Chinese bovine enteroviruses and sequence analysis of their complete genomes.

Abstract

In this study, RNA corresponding to bovine enterovirus (BEV) was detected in 24.6 % of faecal samples (17/69) from diarrheic and healthy cattle in six different areas in China by an RT-PCR screening method. Furthermore, two cytopathic agents, designated as BHM26 and BJ50, were isolated from the bovine diarrheic fecal samples. During passage in MA104 cells, ultrathin sections of virus-infected monolayers were examined using a transmission electron microscope, and a large number of symmetrical virus crystals were seen in the cytoplasm, with monomorphic small viral particles of 27-30 nm in diameter. The full-length RNA genomes were 7433 and 7416 nucleotides long, respectively, with a genome organization analogous to that of picornaviruses. Phylogenetic analysis of the VP1 and VP3 capsid protein coding sequences suggested that the viruses BHM26 and BJ50 belong to genotype 2 of the BEV cluster B (BEV-B). In addition, sequence comparisons of the 5' and 3' UTRs and P1, P2 and P3 subgenomic regions of the two isolates suggested that there were intergenotypic recombination events occurring during evolution of the BHM26 and BJ50 isolates.