浙江部分地区猪瘟流行现状的调查与分析

Investigation and analysis of epidemic situation of classical swine fever in parts of Zhejiang

为了解当前浙江省猪瘟流行情况,对浙江省8个地市的18个疑似猪瘟发病场的流行病学资料进行调查与分析。结果表明,浙江省猪瘟以非典型为主,典型猪瘟也同时存在,绝大多数都是在外界诱因(如长途运输、去势、注苗)诱导或其他病原感染下发生,多为3月龄以内仔猪发病且病程较长。母猪存在隐性感染,部分表现为繁殖障碍,一些临床健康猪存在带毒问题。此外,从疑似猪瘟的38份病料中检出猪瘟病毒(CS-FV)、猪生殖与呼吸综合征病毒(PRRSV)和猪圆环病毒Ⅱ型(PCVⅡ),检出率分别为47.37%,44.7%和23.68%;而PRRSV、PCVⅡ分别与CSFV的混合感染率为33.3%和11.1%。分子流行病学调查结果表明,浙江猪瘟流行株与CSFV石门毒株(Shimen株)和CSFV兔化弱毒株(HCLV株)2个传统毒株的E2核苷酸同源性分别为81.2%～83.0%和83.1%～84.0%,与不同厂家的弱毒疫苗株核苷酸同源性为81.7%～82.6%,说明浙江省猪瘟流行株正朝远离疫苗毒发展并呈现遗传多样性。

In order to understand the current epidemic status of classical swine fever（CSF） in Zhejiang,a survey of 18 pig farms suspected of CSF in 8 cities of Zhejiang Province was conducted.The results indicated that CSF cases mainly showed a typical or mild symptom.Most of cases were attributed to outside inducement,such as long distance transport,castration and vaccination,and other kinds of pathogen infection.Majority of cases occurred in pigs under 3 months of age and had a long course of disease.CSFV was detected in some clinical health sows and reproductive problem sows.The detection rates of CSFV,porcine reproductive and respiratory syndrome virus（PRRSV） and porcine circovirus type Ⅱ（PCVⅡ） from 38 specimens suspected for CSF were 47.37%,44.7% and 23.68%,respectively.The mixed infection rates of PRRSV and CSFV or PCVⅡ and CSFV were 33.3% and 11.1%,respectively.Molecular epidemic investigation results indicated that E2 nucleotide homology of epidemic CSFV strains in Zhejiang compared with Shimen strain,HCLV strains and the attenuated vaccine strains from different manufacturers were 81.2%-83.0%,83.1%-84.0% and 81.7%-82.6%,respectively,indicating that the epidemic strains of CSFV in Zhejiang was moving away from the vaccine strain and showed genetic diversity.