2011年云南楚雄地区狂犬病疫情分子流行病学研究

Molecular epidemiology on an outbreak of rabies in Yunnan, China, in 2011

目的针对2011年发生于云南楚雄地区的狂犬病疫情开展分子流行病学调查分析。方法通过直接免疫荧光试验（DFA）和RT—PCR方法对采集样本进行检测。采用DNAstar中MegAlign软件和MEGA3．1软件Neighbour—joining（NJ）方法分别进行病毒样本N基因的同源性分析和系统进化分析。结果在23份脑组织或脑脊液标本中，11份实验室检测结果为阳性，阳性率为47．8％。核蛋白（N）基因同源性结果表明，来自犬只的病毒样本与基因Ⅰ型Asia1a亚型病毒同源性最高，核苷酸同源性为99．2％～99．4％之间，与Asia2c基因亚型病毒核苷酸同源性为88．5％-89．6％。进化树分析结果表明，本研究分离到的病毒样本与Yunnan—ZT07处于同一进化分支内。结论引发本次疫情的狂犬病毒属于基因Ⅰ型Asia1a亚群，且此次疫情可能与2007年云南昭通流行毒株Yunnan—ZT07的输入关系密切。

Objective To investigate the molecular epidemiologic features of rabies outbreak in Chuxiong District in Yunnan Province, China, in 2011. Methods Brain tissue specimens from dogs and domestic animals were collected and the presence of rabies virus was determined by direct immunofluorescence （DFA） and reverse transcription-polymerase chain reaction （RT-PCR） assays. Homology and phylogenetie analyses were performed using the MegAlign and MEGA3.1 software, respectively. Results Eleven of 23 brain tissue specimens were confirmed positive for rabies virus by both DFA and RT-PCR assays. A nucleotide sequence homology of 99.2%-99. 4% existed between the two nucleoprotein （N） gene fragments from positive specimens and the Asia la subgroup of genotype 1 Lyssavirus. Conclusion Phylogenetic analysis indicated that the rabies viruses causing this outbreak belonged to the Asia la subgroup of genotype 1 Lyssavirus, which is closely related to the Yunnan-ZT07 specimen isolated in Zhaotong District, Yunnan Province, in 2007.