深圳市腹泻患者星状病毒感染的分子流行病学特征

Genetic characteristics of Astrovirus isolated from patients with diarrhea in Shenzhen, Guangdong, China, from January 2010 to December 2011

目的了解深圳地区感染性腹泻中星状病毒的感染情况，并研究其分子流行病学特点。方法采集深圳市2010年1月至2011年12月2083例疑似腹泻患者粪便标本，同时采集30例健康人粪便标本作为对照，采用荧光RT-PCR检测星状病毒核酸；然后使用特异性引物，对星状病毒核酸阳性标本进一步采用RT—PCR方法扩增星状病毒的ORF2区域，对PCR扩增产物经纯化、测序后进行序列分析，同时对病例的流行病学资料进行统计分析。结果星状病毒检出率为1．39％（29／2083）；其中6月龄以下、6～11月龄、12—35月龄和36月龄以上患者检出率分别为2．96％（5／169）、1．48％（8／707）、2．48％（3／121）和1．20％（13／1086）；星状病毒在冬季检出率较高，春季次之，夏季和秋季则较少发生。对ORF2区域进行基因测序和分析显示，深圳地区星状病毒以HAstV．1为主要流行株，HAstV-2、HAstV-5亦有检出，其他型别则未检出。其中HAstV-1又可分为3个亚组，分别与GenBank上的德国株（AY720892）、印度株（AB551380）和巴西株（AY846638）有较高的亲缘关系，其核苷酸同源性分别为98．3％-99．1％、96．0％～100％和98．0％～100％。结论星状病毒是深圳地区病毒性腹泻的重要病原之一，HAstV-1是深圳地区星状病毒的主要流行株，应加强对星状病毒腹泻的监冽。

Objective To investigate Astrovirus infection status and indentify its molecular characteristics in Shenzhen. Methods During January 2010 to December 2011,2083 stool samples were eollected from patients with suspected diarrhea and 30 stool samples were collected from healthy people in Shenzhen. The nucleic acids extracted from the samples were detected by real-time polymerase chain reaction （real-time PCR）. The sequences of ORF2 of the Astrovirus positive samples were amplified by RT-PCR, and then the products were sequenced after purification. The phylogenetic tree was constructed to analyze the nucleotide sequence homology between those sequences and the sequences of reference strains available in the GenBank database. Results 29 samples of 2083 were Astrovirus positive （ 1.39%, 29/2083）. The positive rates for patients under 6 months, 6-11 months, 12-35 months and above 36 months were 2.96% （5/169）, 1.48% （8/707）, 2.48% （3/121） and 1.20% （13/1086） respectively. The Astrovirus infection was commonly found in winter, followed by spring, but seldom occurred in summer and autumn. According to the analysis on the gene sequencing, strains of HAstV-1, HAstV-2 and HAstV-5 were detected, of which HAstV-1 was the predominant strain. The HAstV-1 strains could further be divided into three subtypes, which had high phylogenetic relationships with Dresden of Germany （ AY720892）, MASTO2392 of India （ AB551380）, and 1165 of Brazil （AY846638） in GenBank, with a nucleotide sequence homology of 98.3%-99.1%, 96.0%- 100% and 98.0% -100% respectively. Conclusion HAstV was one of the important pathogens causing viral diarrhea in Shenzhen and HAstV-1 was the predominant sin.in. Therefore, it is necessary to strengthen the surveillance for diarrhea caused by Astrovirus infection.