Jing Yi, Wang Xia, Tang Sanyi, Wu Jianhong
School of Mathematics and Information Science, Shaanxi Normal University, Xi'an 710062, PR China.
School of Mathematics and Information Science, Shaanxi Normal University, Xi'an 710062, PR China.
J Theor Biol. 2017 Mar 7;416:161-179. doi: 10.1016/j.jtbi.2016.12.014. Epub 2016 Dec 27.
Epidemics of dengue fever in China were reported before 1940 and the outbreak of dengue fever in Guangdong province in 2014 is the most serious so far. The important question is what factors account for this serious outbreak, and how to evaluate the sensitivity of the multiple factors including weather variables and human actions on the dengue disease. Therefore, according to the relations among the temperature (daily mean temperature (DMT) and diurnal temperature range (DTR)), vector parameters and reproduction number we have proposed the analytical formula for the relative vector's capacity and effective reproduction number, and then we have the formula for the likelihood function by employing the generation interval-informed method. This allows us to estimate the unknown vector parameters by the maximum likelihood method and carry out the sensitivity analysis. The correlations between the density of mosquito vectors (the Breteau index (BI), the adult mosquito density) and the daily newly reported cases of four different districts of Guangzhou city have been studied by using the Pearson correlation and cross-correlation analyses. Our findings indicate that both the BI and the adult mosquito density are statistically significantly correlated with the daily newly reported cases, and the vector parameters are closely related to the DMT and DTR with relative complex relationships, which influence the effective reproduction number comprehensively. Moreover, the trend of the effective reproduction number is consistent with daily newly reported cases, which confirms the effectiveness of the government control measures. Sensitivity analysis results indicate that the temperature can be either an effective barrier or a facilitator of vector-borne diseases, and consequently weather variable may result in complexity of dengue disease control.
中国在1940年之前就有登革热疫情报告，2014年广东省的登革热疫情是迄今为止最严重的。重要的问题是哪些因素导致了这次严重疫情，以及如何评估包括气象变量和人类活动在内的多种因素对登革热疾病的敏感性。因此，根据温度（日平均温度（DMT）和昼夜温差（DTR））、媒介参数和繁殖数之间的关系，我们提出了相对媒介能力和有效繁殖数的解析公式，然后采用世代间隔告知法得到似然函数公式。这使我们能够通过最大似然法估计未知的媒介参数并进行敏感性分析。利用Pearson相关性分析和交叉相关性分析研究了广州市四个不同区的蚊媒密度（布雷图指数（BI）、成蚊密度）与每日新报告病例之间的相关性。我们的研究结果表明，BI和成蚊密度与每日新报告病例在统计学上均显著相关，媒介参数与DMT和DTR密切相关，关系相对复杂，综合影响有效繁殖数。此外，有效繁殖数的趋势与每日新报告病例一致，这证实了政府防控措施的有效性。敏感性分析结果表明，温度既可以是媒介传播疾病的有效屏障，也可以是促进因素，因此气象变量可能导致登革热疾病控制的复杂性。
