Phylogenetic analysis of the VP2 gene of canine parvoviruses circulating in China.

Sequences of the full-length gene encoding the main capsid protein VP2 of 22 strains of canine parvovirus (CPV), isolated from domestic dogs in China between 1983 and 2008, were determined and analyzed in comparison with the sequences of 30 other strains of CPV from China and reference CPV isolates retrieved from GenBank. Three types of CPV, including CPV-2, CPV-2a, and CPV-2b, were detected, and CPV-2a (with 297-Ala mutation) was predominant in China. The unique Ile-324 mutation in the VP2 of Chinese CPV isolates was detected, as compared with a Tyr-324 in the VP2 of the reference CPV strains. A phylogenetic tree constructed from the VP2 genes showed that most of the Chinese strains classified in a cluster consisting of Chinese and Korean field isolates, which were distinct from Thai, U.S., and Italian isolates.