应用SEIAR模型分析某儿童中心诺如病毒肠胃炎疫情

目的 通过调查分析诺如病毒引起的感染性胃肠炎疫情,为防控校园诺如病毒疫情暴发提供依据。 方法 收集深圳市某儿童中心病例,采集标本,进行现场流行病学调查和实验室检测,并建立易感-潜伏期-显性/隐性感染者-移出者模型。 结果 本起诺如病毒引起的暴发性疫情共计104名病例,罹患率19.81%(104/525),其中呕吐90例(86.54%)、腹痛64例(61.54%)和腹泻11例(10.58%),流行曲线呈点源暴露模式。易感-潜伏期-显性/隐性感染者-移出者模型显示传染率=7.590,c=0.143,罹患率将达到 40.19%(211/525),整个流行过程持续20 d。将不同比例进行拟合,显示只有当环境消毒达到10%β时,可明显降低累计发病人数约72人,但疫情的持续时间延长。 结论 通过环境消毒降低诺如病毒环境中的密度,并不能有效抑制疫情的发展,但关闭学校能够有效减少患病人数,且效果显著,优于采用隔离和环境消毒的联合防控措施。

Application of SEIAR model to analyzing the epidemic situation of norovirus gastroenteritis in a children's center

Objective To investigate and analyze an infectious gastroenteritis outbreak caused by norovirus, and to provide a basis for prevention and control of norovirus outbreak in the school. Methods Cases and specimens were collected from a children's center in Shenzhen City. On-site epidemiological investigation and laboratory testing were conducted, and a susceptible-exposed-infectious/asymptomatic-removed (SEIAR) model was set up. Results A total of 104 cases of infectious gastroenteritis caused by norovirus were involved in this outbreak, with an attack rate of 19.80% (104/525), including 90 cases of vomiting (86.54%), 64 cases of abdominal pain (61.54%) and 11 cases of diarrhea (10.58%). The epidemic curve showed a point source exposure pattern. The SEIAR model revealed that the infection rate and c were 7.590 and 0.143, respectively. The attack rate would reach 40.19% (211/525), and the entire epidemic process would last 20 days. Moreover, it was found that only when the environmental disinfection reached 10% β, the cumulative number of cases could be significantly reduced, but the duration of the epidemic was also extended. Conclusion Reducing norovirus through environmental disinfection cannot effectively suppress the development of the epidemic, but closing the school can effectively reduce the number of patients, and the effect is significant, which is superior to the joint prevention and control measures of isolation and environmental disinfection.