Genetic typing and epidemiologic observation of bovine viral diarrhea virus in Western China.

Whole blood samples (472) were collected during the period of 2006-2008 from 15 cattle farms in seven districts of the Xinjiang Uygur Autonomous Region, which is a major pastoral area and represents 1/6 of Chinese territory. Bovine viral diarrhea virus (BVDV) was detected by nested reverse transcription polymerase chain reaction assay (RT-nPCR) and sequenced within the 5'-untranslated region of the genome. Approximately 43% (202 samples) were BVDV-positive. Of the positive samples, 24 were chosen for further sequencing, sequence comparisons, and phylogenetic reconstructions. The phylogenetic reconstructions demonstrated that these isolates clustered into either BVDV1b (18 samples) or BVDV1c (six samples) subgenotypes. None of the isolates sequenced showed any cytopathic effect in culture. Unlike previously published studies in Chinese cattle, no BVDV2 genotypes were detected. These results indicate that the predominant subgenotypes in Xinjiang are BVDV1b and BVDV1c. This finding can be useful for further BVDV epidemiological study in China.