传染病动力学模型在登革热疫情防控中的应用

目的 应用传染病动力学模型研究登革热暴发流行的传播规律,并对灭蚊、病例隔离等防控措施的效果进行定量评价。 方法 根据登革热疾病的自然史建立登革热暴发流行的SEIR模型。收集2014年广州市的登革热暴发疫情数据,将模型与之拟合,利用χ²检验评价模型模拟数据与实际疫情数据的拟合优度,获得模型关键参数。应用模型模拟一起由输入性病例引发的社区暴发疫情,并对无干预、灭蚊、隔离、灭蚊+隔离状态下的疫情发展趋势及不同防控效果进行定量评价,寻找最优防控方案。 结果 通过模型模拟,在10 000人的社区中输入1例感染登革II型病毒病例,未干预状态下,登革热疫情发展很快,发病人数呈直线上升趋势,疫情持续超过100 d,超过450人发病。采取隔离措施后,疫情控制效果不明显。采取灭蚊措施后,疫情很快得到控制。采取灭蚊+隔离综合措施的效果和采取单项灭蚊措施效果无差别,越早采取灭蚊措施效果越好。 结论 在登革热的暴发疫情处置中,灭蚊是最关键的防控措施,一旦疫情在人群中形成传播,隔离并不能达到阻断传染源的目的 ,只能作为疫情控制的辅助措施。

Application of epidemic dynamics model to prevention and control of dengue fever epidemic

Objective To study the transmission law of dengue fever outbreaks by applying epidemic dynamics model, and to make a quantitative evaluation on the effect of prevention and control measures, such as anti-mosquito and case isolation. Methods Based on the natural history of dengue fever, a susceptible-exposed-infectious/asymptomatic-removed (SEIR) model of dengue fever outbreaks and epidemics was built. Data concerning dengue fever outbreaks in Guangzhou City in 2014 were collected for matching with the model. χ² test was used to evaluate the goodness-of-fit of the simulated data and the practical epidemic data, and key parameters of the model were acquired. A community-based outbreak caused by an imported case was simulated by applying the model. A quantitative evaluation was made for assessing the development tendency of the epidemic situation under non-intervention, anti-mosquito, isolation, and anti-mosquito combined with isolation as well as the effects of different prevention and control measures so as to seek an optimized scheme of prevention and control. Results Simulations using the model were conducted, assuming one case of dengue virus type II was imported to a community with 10,000 residents. Dengue fever epidemic developed quickly without the intervention, the number of the infected cases showed an upward trend in a straight line, and the epidemic lasted for over 100 days, involving more than 450 cases. The effect of the epidemic control was not obvious after adopting isolation measures, but the epidemic situation was well controlled after adopting anti-mosquito measures. No difference was found in the effect of anti-mosquito betweentakingcomprehensive measures based on anti-mosquito combined with isolation and adopting single anti-mosquito measure. The sooner the anti-mosquito measure was taken, the better the effect showed. Conclusion Anti-mosquito is the most critical measure in prevention and control of dengue fever epidemic.Once the epidemic spreads among the population,isolation cannot reach the purpose to block the source of infection, and it can only be taken as a supplementary measure to control the epidemic outbreak.