Environmental Chemistry Laboratory (LCE), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Laboratory of Geographic Information Systems (LASIG), School of Architecture, Civil and Environmental Engineering (ENAC), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
Sci Rep. 2019 Jul 11;9(1):10042. doi: 10.1038/s41598-019-46475-3.
In developing countries, the waterborne transmission of hepatitis E virus (HEV), caused by HEV genotypes 1 (HEV-1) and 2 (HEV-2), leads to the onset of large recurrent outbreaks. HEV infections are of particular concern among pregnant women, due to very high mortality rates (up to 70%). Unfortunately, good understanding of the factors that trigger the occurrence of HEV epidemics is currently lacking; therefore, anticipating the onset of an outbreak is yet not possible. In order to map the geographical regions at higher risk of HEV epidemics and the conditions most favorable for the transmission of the virus, we compiled a dataset of HEV waterborne outbreaks and used it to obtain models of geographical suitability for HEV across the planet. The main three variables that best predict the geographical distribution of HEV outbreaks at global scale are population density, annual potential evapotranspiration and precipitation seasonality. At a regional scale, the temporal occurrence of HEV outbreaks in the Ganges watershed is negatively correlated with the discharge of the river (r = -0.77). Combined, our findings suggest that ultimately, population density and water balance are main parameters influencing the occurrence of HEV-1 and HEV-2 outbreaks. This study expands the current understanding of the combination of factors shaping the biogeography and seasonality of waterborne viral pathogens such as HEV-1 and HEV-2, and contributes to developing novel concepts for the prediction and control of human waterborne viruses in the near future.
在发展中国家，由 HEV 基因型 1（HEV-1）和 2（HEV-2）引起的戊型肝炎病毒（HEV）经水传播导致大规模反复爆发。戊型肝炎感染在孕妇中尤为令人关注，因为死亡率非常高（高达 70%）。不幸的是，目前人们对引发戊型肝炎流行的因素了解甚少；因此，目前还不可能预测疫情的爆发。为了绘制戊型肝炎流行的高风险地理区域图，并确定有利于病毒传播的条件，我们编制了一组戊型肝炎水传播暴发数据集，并利用该数据集获得了全球范围内戊型肝炎地理适宜性模型。最佳预测全球尺度戊型肝炎暴发地理分布的三个主要变量是人口密度、年潜在蒸散量和降水季节性。在区域尺度上，恒河流域戊型肝炎暴发的时间发生与河流流量呈负相关（r = -0.77）。综合来看，我们的研究结果表明，最终，人口密度和水平衡是影响 HEV-1 和 HEV-2 暴发的主要参数。本研究扩展了当前对影响 HEV-1 和 HEV-2 等水传播病毒病原体生物地理学和季节性的因素组合的理解，并为未来预测和控制人类水传播病毒提供了新的概念。
