猪繁殖与呼吸综合征病毒感染的诊断及其分子特点

采用流行病学调查、临床症状观察、病理学检查、病毒分离、分离毒株测序以及遗传演化分析的方法,对北京及其周边地区4个猪场剖检的4头猪进行分析。结果:流行病学和临床症状表现为急性高热性传染病;病理学观察为非化脓性脑炎和间质性肺炎等多器官严重的病理变化;RT-PCR和病毒分离确定该疫情的主要病原是猪繁殖与呼吸综合征病毒(PRRSV)。与典型PRRSV感染不同的是:成年猪感染率达50%以上,病死率达80%以上;PRRSV分离株全基因序列分析表明属于PRRSV北美洲型,特别是PRRSV NSP2不连续缺失30个氨基酸,说明此次流行的PRRSV毒株可能为高致病性毒株。

Diagnosis of porcine reproductive and respiratory syndrome virus infection and its molecular characteristics

Bases on the epidemiological investigation,clinical observation,pathological examination,virus isolation,gene sequencing and phylogenetic analysis,the diseased pigs in four pig farms from Beijing and its surrounding areas were diagnosed.The diseased pigs mainly manifested with high fever in clinical expression;the pathological examination result showed non-suppurative encephalitis,interstitial pneumonia and the other severe pathological damages;virus isolation,serological test and RT-PCR amplification further confirmed the pathogen was porcine reproductive and respiratory syndrome virus(PRRSV).Different from the typical case,the disease showed high morbidity and mortality in the adult hogs,up to 50% and 80%,respectively.The sequences analysis of whole genome indicated that the isolates belong to the Northern American type PRRSV.The discontinuous deficiency with 30 amino acids in NSP2 gene was found,which is characteristic of highly pathogenetic PRRSV strain.