Department of Biodiversity and Molecular Ecology, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige (Trento), Italy.
Epilab-JRU, FEM-FBK Joint Research Unit, Province of Trento, Italy.
Sci Rep. 2018 Sep 18;8(1):14005. doi: 10.1038/s41598-018-32401-6.
An intensified and continuous West Nile virus (WNV) spread across northern Italy has been observed since 2008, which caused more than one hundred reported human infections until 2016. Veneto is one of the Italian regions where WNV is considered endemic, and the greatest intensity of circulation was observed during 2013 and 2016. By using entomological data collected across the region in those years, we calibrated a temperature-driven mathematical model through a Bayesian approach that simulates the WNV infection in an avian population with seasonal demography. We considered two alternative routes of life cycle re-activation of the virus at the beginning of each vector breeding season: in the first one the virus is maintained by infected birds, in the other by diapausing mosquitoes previously infected. Afterwards, we computed seasonal risk curves for human infection and quantified how they translate into reported symptomatic cases. According to our results, WNV is more likely to be re-activated each year via previously infected mosquitoes. The highest probability of human infection is expected to occur in August, consistently with observations. Our epidemiological estimates can be of particular interest for public health authorities, to support decisions in term of designing efficient surveillance plans and preventive measures.
自 2008 年以来，意大利北部一直观察到西尼罗河病毒（WNV）的强化和持续传播，截至 2016 年，已报告超过 100 例人类感染病例。威尼托是意大利WNV 流行的地区之一，2013 年和 2016 年观察到的循环强度最大。通过使用这些年份在该地区收集的昆虫学数据，我们通过贝叶斯方法对一个受温度驱动的数学模型进行了校准，该模型模拟了具有季节性人口统计学的鸟类群体中的 WNV 感染。我们考虑了在每个媒介繁殖季节开始时病毒两种替代的生命周期再激活途径：第一种途径是受感染的鸟类维持病毒，另一种途径是先前感染的休眠蚊子。之后，我们计算了人类感染的季节性风险曲线，并量化了它们如何转化为报告的症状病例。根据我们的结果，WNV 每年更有可能通过先前感染的蚊子重新激活。预计人类感染的最高概率将出现在 8 月，这与观察结果一致。我们的流行病学估计对于公共卫生当局特别有意义，有助于在设计有效的监测计划和预防措施方面做出决策。
