云南红河州小反刍兽疫的血清学及分子流行病学调查

Serological and Molecular Epidemiological Investigation of Peste des Petits Ruminants in Honghe Autonomous Prefecture of Yunnan

为掌握小反刍兽疫在云南省红河州的流行情况及疫苗防控效果,应用竞争酶联免疫吸附试验(ELISA),对该州13个县市采集自人工免疫山羊的920份血清进行抗体检测,同时应用反转录-聚合酶链反应(RT-PCR)对215份山羊组织样品检测小反刍兽疫病毒(PPRV)核衣壳蛋白(N)基因小片段,并取PCR扩增呈阳性的组织样品进一步做N基因大片段的克隆与测序,最后与国内外参考毒株进行核苷酸同源性比较及进化关系分析。调查结果表明,该州小反刍兽疫血清抗体平均阳性率为70.65%,病毒核酸阳性率为20.46%;当地流行毒株与国内其他毒株同源性最高,均属于基因Ⅳ系毒株,并与印度株和土耳其株进化关系相近。据此推测,当地流行毒株可能最初从国外传入,再伴随引种传入云南。调查证实,以国外基因Ⅱ系毒株制成的弱毒疫苗,虽与我国毒株不同基因系,但具有较高的免疫保护力。

In order to grasp the epidemic situation and vaccination efficacy of peste des petits ruminants in Honghe autonomous prefecture,Yunnan province,we detected 920 serum samples collected from vaccinated goats covering 13 counties using competitive enzyme-linked immunosorbent assay(ELISA),and examined the nucleocapsid protein(N)gene of PPRV from 215 tissue samples using reverse transcription-polymerase chain reaction(RT-PCR),then cloned and sequenced PCR positive samples,followed by further comparison of nucleic acid homology with domestic and foreign referenced strains and analysis of phylogenetic relationship.The study indicated that the average positive rate of serum antibody was 70.65%,the positive rate of viral RNA was 20.46%.The strains prevalent in Honghe Autonomous Prefecture had the highest homology with the other strains of PPRV in China,all of them belonged to genotype IV and were similar in N gene to those strains originated in India and Turkey,speculating that the local strains are likely to be introduced from other provinces and previously from neighbor countries.The survey confirmed the attenuated live vaccine of typeⅡgene made of the exotic isolate provided sufficient immune protection,although it differs from the domestic strains of prevalence.