Identification and phylogenetic analysis of the sheep pox virus Shanxi isolate

A strain of virus was successfully isolated from a Demei sheep with typical symptoms of sheep pox virus (SPPV) in Shanxi province in China (SPPV-Shanxi) and identified using hematoxylin and eosin staining, electron microscopy, neutralization testing, and PCR. Identification results proved a SPPV-Shanxi infection in the sheep. The full-length P32 gene (an immunogenic envelope protein of Capripoxvirus) and the SPV64 gene (the L5R allele in SPPV) were cloned and sequenced. Phylogenetic trees were constructed based on the nucleotide and amino acid sequences of the two genes. Based on the phylogenetic tree, the SPPV-Shanxi isolate clustered together with AV40 (a Chinese vaccine strain) was closer to FJ748487 (SPPV India isolate) and AY077834 (SPPV Kazakhstan isolate). The amino acid sequence analysis revealed several unique amino acid substitutions between the SPPV-Shanxi isolate and other isolates. This is the first report that an outbreak of SPPV occurred in Shanxi province in China. There are no reports on the molecular characterization of SPPV-Shanxi isolates based on P32 and SPV64 genes. Our findings may provide the information on the genotype of the etiologic prevalence responsible for the SPPV outbreak in Shanxi province