江苏省无锡市某幼儿园一起由EV 71引起的手足口病暴发疫情调查

A survey of the outbreak of hand-foot-mouth disease caused by EV 71 in a kindergarten in Wuxi City,Jiangsu Province

目的调查无锡市某幼儿园一起由肠道病毒71型(EV 71)引起的手足口病暴发疫情,为有效防控手足口病暴发疫情提供科学依据。方法对发病病例进行个案调查,采用实时荧光定量反转录-聚合酶链反应(RT-PCR)对咽拭子和肛拭子标本进行EV 71、Cox A16等肠道病毒检测,采用描述性流行病学方法对调查数据进行分析。结果本次疫情从2017年5月6日~2017年6月29日,持续55 d。总罹患率为3.89%,呈现明显的时空聚集性,波及16个班级,出现3个发病高峰。小班罹患率最高为8.58%,大班、中班罹患率分别为1.96%和2.25%,大中、小班学生间罹患率差异有统计学意义(χ~2=28.419,P<0.01)。男女罹患率分别为4.23%和4.50%,差异无统计学意义(χ~2=0.053,P=0.817)。年龄分布在3~7岁,3岁组罹患率最高为16.67%,4岁组、5岁组、6~岁组罹患率分别为6.25%、2.12%和2.20%,不同年龄组间罹患率差异有统计学意义(χ~2=36.357,P<0.01)。停课及时性与疫情持续时间(rs=0.688,P=0.028)、发病数(rs=0.659,P=0.038)存在正相关。病原学检测结果显示4例病例EV 71阳性,其余标本均为阴性。结论本次幼儿园手足口病暴发疫情由EV 71病毒感染引起。初期公共教室未暂停使用,部分班级达到停课标准后未及时停课,周边私人幼托班防控措施落实不到位是此次疫情的主要原因。应提高儿童EV 71疫苗接种率,有效减少EV 71相关手足口病疫情的发生。

Objective To study the outbreak of hand-foot-mouth disease caused by EV 71 in a kindergarten in Wuxi,and to provide scientific evidence for effective prevention and control. Methods All cases were performed with individual case investigation. Real-time fluorescence quantitative reverse transcription-polymerase chain reaction（ RT-PCR） was used to detect enteroviruses such as EV 71 and Cox A16 in throat swabs and anal swabs. Descriptive epidemiological method was conducted to analyze the survey data. Results The outbreak lasted 55 days from May 6,2017 to June 29,2017,and the overall attack rate was3. 89%. The outbreak with spreading to 16 classes and three peaks of incidence showed obvious spatial and temporal clustering. The highest attack rate of small classes was 8. 58%,and the attack rates of the top and middle classes were respectively1. 96% and 2. 25%. There was a statistically significant difference on the attack rates among different grades（ χ^2= 28. 419,P〈0. 01）. The attack rates of male and female were 4. 23% and 4. 50%,and there was no statistically significant difference on the attack rates between male and female（ χ^2= 0. 053,P = 0. 817）. The age distribution of the outbreak was at the age of 3 - 7. The highest attack rate was 16. 67% in the 3 year old group,the incidence of the 4 year old group,the 5 year old group,the 6 year old group and the above group were 6. 25%,2. 12% and 2. 20% respectively. There was a significant difference on the attack rates among different age groups（ χ^2= 36. 357,P〈0. 01）. The timeliness of closure was positively related to the duration of the epidemic（ rs= 0. 688,P = 0. 028） and the number of cases（ rs= 0. 659,P = 0. 038）. The result of etiological examination showed that 4 cases were positive for EV 71,and the other specimens were negative. Conclusion The outbreak of hand-foot-mouth disease in the kindergarten was caused by EV 71 virus infection. In the early period,public classrooms were not suspended,and classes were not closed in time after the suspension of classes. The lack of preventive and control measures for private child care classes was the main reason for the outbreak. Children＇s EV 71 vaccination rates should be increased to effectively reduce the incidence of EV 71 related hand-foot-mouth disease.