2002年上海儿童手足口病病例中肠道病毒71型和柯萨奇病毒A组16型的调查

Detection of enterovirus 71 and coxsackievirus A16 from children with hand, foot and mouth disease in Shanghai, 2002

目的对上海地区2002年4—6月儿童手足口病流行期间的手足口病患儿进行病原学调查。方法采集手足口病患儿的疱疹液、粪便、咽拭子进行病毒分离;分别用肠道病毒组合血清、肠道病毒71型(EV71)单价血清和柯萨奇病毒A组16型(CA16)单价血清对分离到的病毒进行中和试验定型;对不能定型的病毒株再分别用EV71和CA16的VP1基因的特异性引物进行RT-PCR鉴定。结果从72例患儿共采集102份标本,由其中67例患儿的91份标本分离到病毒;所有分离到的病毒株均不能用血清学方法进行定型;进一步经RT-PCR检测,58例为CA16,9例为EV71,二者之比为6.4∶1;其中2例的EV71病毒株经中国疾病预防控制中心进行序列分析,认为属新的C4基因亚型;在EV71阳性病例中1例并发脑炎,出现抽搐、休克、昏迷、呼吸衰竭。结论从该组手足口病患儿检测到的主要病原是CA16和EV71;在上海地区首次报道与EV71感染相关的手足口病合并重症脑炎病例。

Objective It was noticed that coxsackievirus A16 （CA16） and enterovirus 71 （EV71） were two major etiological agents of hand, foot and mouth disease （HFMD） in children. Recently there were several large outbreaks of HFMD in the Asia-Pacific region, and there was a propensity to cause severe complications or death in children under 5 years of age. The severe forms were associated with EV71 infection. Although epidemics of HFMD have been reported in the mainland of China, few reports about EV71 as the pathogen of HFMD epidemics are available. The present study was conducted to investigate the causal agent of an HFMD epidemic in children in Shanghai from April to June of 2002. Methods Totally 102 specimens （including vesicle fluid, stool and throat swabs） were collected from 72 patients with HFMD. The specimens were inoculated into Vero and/or RD cells. At first all the isolates were respectively neutralized by the RIVM pools of enterovirus antiserum, the type-specific antisera to EV71 or to CA16. Secondly all untyped isolates were tested by RT-PCR assay with two specific primer pairs for VP1 genes of EV71 and CA16 respectively. The EV71 and CA16 were identified depending on the size of PCR products. Sequence analyses of VP1 genes of 9 virus strains were performed by the laboratory of China CDC. Results Viruses were isolated from 91 specimens from 67 patients. Serotyping by neutralization failed for all the isolates. But the RT-PCR results indicated that the viruses isolated from 78 specimens from 58 patients were identified as positive for CA16 and the isolates from 13 specimens from 9 patients were identified as positive for EV71, the ratio between CA16 and EV71 was 6. 4： 1. The results of sequence analyses were consistent with those of PCR assay. Two EV71 strains isolated in this study belonged to a new lineage （CA） within genogroup C. One patient with EVTl-associated HFMD had a complication of encephalitis with convulsion, shock, coma and dyspnea. Conclusion CA16 and EV71 were the primary causes of HFMD during the epidemic. It was the first report of EVTl-associated severe encephalitis occurred in patients with HFMD in Shanghai.