First isolation of new canine parvovirus 2a from Tibetan mastiff and global analysis of the full-length VP2 gene of canine parvoviruses 2 in China.

Zhijun Zhong,Juan Zhao,Ziyao Zhou,Liuhong Shen,Xuefeng Cao,Xiaoyang Xu,Yi Geng,Guangneng Peng,Zhihua Ren,Xiaobin Gu,Xuehan Liu,Luqi Liang

doi:10.3390/ijms150712166

Zhijun Zhong, Juan Zhao + Show 10 more

Open Access

https://doi.org/10.3390/ijms150712166

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Abstract

Canine parvovirus 2 (CPV-2) was first identified in 1978, and is responsible for classic parvoviral enteritis. Despite the widespread vaccination of domestic carnivores, CPVs have remained important pathogens of domestic and wild carnivores. In this study, we isolated CPV-2 from Tibetan mastiffs and performed a global analysis of the complete VP2 gene sequences of CPV-2 strains in China. Six isolates were typed as new CPV-2a, according to key amino acid positions. On a phylogenetic tree, these six sequences formed a distinct clade. Five isolates occurred on the same branch as KF785794 from China and GQ379049 from Thailand; CPV-LS-ZA1 formed a separate subgroup with FJ435347 from China. One hundred ninety-eight sequences from various parts of China and the six sequences isolated here formed seven distinct clusters, indicating the high diversity of CPVs in China. Of 204 VP2 sequences, 183 (91.04%) encoded the mutation Ser297Ala, regardless of the antigenic type, implying that most Chinese CPV-2 strains contain the VP2 mutation Ser297Ala. However, the biological significance of this change from prototype CPV-2a/2b to new CPV-2a/2b types remains unclear. This study is the first to isolate new CPV-2a from the Tibetan mastiff. Our data show that new CPV-2a/2b variants are now circulating in China.

Highlights

Two kinds of parvovirus can infect canines
A specific fragment (826 bp) of the VP2 gene was amplified from the seven samples, confirming the presence of canine parvovirus 2 (CPV-2) in the samples
Cytopathic effects (CPE), including tapering cells, cytomixis, rounding cells, and plaque-forming cells appeared in six cell samples at 6–13 days after inoculation (Figure 1)

Summary

Introduction

Two kinds of parvovirus can infect canines. One is the minute virus of canines (MVC) and the other is canine parvovirus 2 (CPV-2). MVC is referred to as canine parvovirus 1 (CPV-1) and was isolated from a diseased dog in 1970, when it was initially considered a nonpathogenic virus. 1978, a new virus was identified in dogs with hemorrhagic enteritis and leucopenia [1,2]. To differentiate it from CPV-1, the new virus was designated CPV-2. CPV-1 and CPV-2 have both been called parvoviruses, they belong to different genera.

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