Isolation and phylogenetic analysis of orf virus from the sheep herd outbreak in northeast China

Wei Li,Feng Gao,Daniel L Rock,Xiaoqing Liao,Zhangyong Ning,Deguang Song,Kui Zhao,Ming Li,Shuhong Luo,Wenbo Hao

doi:10.1186/1746-6148-8-229

Abstract

BackgroundOrf is a zoonotic and epitheliotrophic contagious disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution. To date, there is little information on the characterization of ORFV strains that are endemic in Mainland China. In addition, the relationship between the severity of disease and the molecular profile of ORFV strains has not been fully elucidated.ResultsFrom the recent outbreak of a sheep herd in Nongan, northeast of China, the novel orf virus (ORFV) strain NA1/11 was successfully isolated. Western blot analysis indicated that the NA1/11 strain cross reacts with monoclonal antibody A3 and infected sheep ORFV antiserum. The purified virions revealed the typical ovoid shape when observed by atomic force microscopy. To determine the genetic characteristics of the NA1/11 strain, the sequences of ORFV011 (B2L), ORFV059 (F1L), ORFV109, ORFV110 and ORFv132 (VEGF) genes were amplified and compared with reference parapoxvirus strains. Non-metric multidimensional scaling (nMDS) was performed to analyze the nucleotide similarities between different ORFV strains.ConclusionsPhylogenetic analysis based on ORFV 011 nucleotide sequences showed that the NA1/11strain was closely related to Xinjiang and Gansu strains. ORFV110 and ORFV132 genes are highly variable. The results revealed that precise phylogenetic analysis might provide evidence for genetic variation and movement of circulating ORFV strains in Northeast China. In addition, nMDS analysis showed that geographic isolation and animal host are likely major factors resulting in genetic differences between ORFV strains.

Highlights

Orf is a zoonotic and epitheliotrophic contagious disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution
Considering heterogeneity of different orf virus (ORFV) field strains, we focused on isolation and characterization of ORFV from lesions during an epidemic of multifocal, persistent, severe, proliferative dermatitis in lambs in China
Clinical gross pathological changes In the sheep herd in Nongan clinical lesions with characteristic symptoms of orf such as papules, pustules, and scabs were recorded in 11 lambs from the flock

Summary

Introduction

Orf is a zoonotic and epitheliotrophic contagious disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution. Known as contagious pustular dermatitis or contagious ecthyma, is an epitheliotrophic disease that mainly affects sheep, goats, wild ruminants, and humans with a worldwide distribution [1-3]. ORFV, the causative agent of orf, is the prototype member of the genus Parapoxvirus belong to the subfamily Chordopoxvirinae of the Poxviridae. This genus includes pseudocowpox virus (PCPV) and bovine papular stomatitis virus (BPSV) in cattle, squirrel parapoxvirus (SPPV), and parapoxvirus of red deer in New Zealand (PVNZ) [11,12]. There are four ORFV strains that have been isolated and completely sequenced, OVIA82 and OV-SA00 [14] in America, NZ2 in New Zealand [13], and D1701 in Germany [15,16]

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