1.南京市疾病预防控制中心 急性传染病防制科;2.南京市疾病预防控制中心 微生物检验科;3.南京市浦口区疾病预防控制中心
Department of Acute Infectious Disease Control and Prevention,Nanjing Center for Disease Control and Prevention
Nanjing key medical specialty (Infectious disease prevention and control)；Jiangsu Province preventive medicine program (Y2018077)
目的：了解柯萨奇病毒A6（coxsackievirus A6，CV-A6）感染情况和排毒时长，指导科学制定防控策略和措施。方法：制定病例定义，搜索病例。经过知情同意，采集某幼儿园所有病例和罹患率较高的小1班、中2班全体儿童的咽拭子和肛拭子标本，RT-PCR检测肠道病毒核酸，对检测阳性的儿童，每间隔1周再次采集标本开展检测，直至连续两次均为阴性时终止采样。结果：儿童罹患率为8.2%（17/208），发现隐性感染者17例。小1班和中2班流行曲线都呈现单峰分布，卫生学调查排除饮食和饮水传播。病原检测显示为CV-A6型肠道病毒核酸阳性。检测阳性者中隐性感染比例为52%（95%CI：34%~69%）。排毒时长中位数为18天（95%CI：16 ~25天），最短为1周内（4天），最长为5.5周（39天），Log-rank检验显示病例与隐性感染者、男性与女性、咽部与肠道排毒时长差异无统计学意义（P＞0.05）。结论：此轮由CV-A6肠道病毒引起的手足口病暴发疫情中，CV-A6隐性感染比例高，排毒时间长。建议提高监测敏感性，病例解除隔离返园（校）、班级复课后应开展持续的健康监测和防控措施。
Objective: To understand the infection situation of coxsackievirus A6 (CV-A6) and the duration of detoxification, and guide and formulate prevention and control strategies and measures scientifically. Methods: The case definition was conductecx and the case search was carried out. After informed consent proving, all the cases were collected and the children's throat swab and anal swab specimens from small class 1 and middle class 2 with higher attack rates were obtained. We used the RT-PCR to carry out intestinal virus nucleic acid detection as well. For children who tested positive, collecting specimens for detection once every two weeks again, the collections would stop if two consecutive tests were negative. Results: The attack rate of children was 8.2% (17/208), and 17 cases of covert infection were found. The epidemic curves of small class 1 and middle class 2 showed unimodal distribution. The transmission of diet and drinking water was excluded after conducting the hygienic investigation. Pathogen detection showed the positive CV-A6 enterovirus nucleic acid. The proportion of covert infection was 52% (95%CI: 34% ~ 69%) in tested positive patients. The median duration of detoxification was 18 days (95% CI: 16 days ~ 25 days), the shortest is one week (4 days), and the longest was up to 5.5 weeks (39 days). Additionally, the Log-rank test showed no statistical significance (P > 0.05) between cases and covert infectors, male and female, the different duration of detoxification of pharyngeal and intestinal. Conclusion: The proportion of CV-A6 covert infection was high, and the duration of detoxification was long in this outbreak. In such contexts, it is suggested to increase surveillance sensitivity. After the cases finished the quarantine and return to the school, continuous health monitoring and prevention and control measures should also be carried out.