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Abstract：
The geographical range of schistosomiasis is affected by the ecology of schistosome parasites and their obligate host snails, including their response to temperature. Previous models predicted schistosomiasis\' thermal optimum at 21.7°C, which is not compatible with the temperature in sub-Saharan Africa (SSA) regions where schistosomiasis is hyperendemic. We performed an extensive literature search for empirical data on the effect of temperature on physiological and epidemiological parameters regulating the free-living stages of S. mansoni and S. haematobium and their obligate host snails, i.e., Biomphalaria spp. and Bulinus spp., respectively. We derived nonlinear thermal responses fitted on these data to parameterize a mechanistic, process-based model of schistosomiasis. We then re-cast the basic reproduction number and the prevalence of schistosome infection as functions of temperature. We found that the thermal optima for transmission of S. mansoni and S. haematobium range between 23.1-27.3°C and 23.6-27.9°C (95% CI) respectively. We also found that the thermal optimum shifts toward higher temperatures as the human water contact rate increases with temperature. Our findings align with an extensive dataset of schistosomiasis prevalence in SSA. The refined nonlinear thermal-response model developed here suggests a more suitable current climate and a greater risk of increased transmission with future warming for more than half of the schistosomiasis suitable regions with mean annual temperature below the thermal optimum.
摘要：
血吸虫病的地理范围受血吸虫寄生虫及其专性寄主蜗牛的生态影响，包括他们对温度的反应.以前的模型预测血吸虫病在21.7°C时的热最佳值，这与血吸虫病流行高的撒哈拉以南非洲（SSA）地区的温度不符。我们进行了广泛的文献搜索，以获取有关温度对生理和流行病学参数的影响的经验数据，这些参数调节了曼氏球菌和嗜血杆菌及其唯一寄主蜗牛的自由生活阶段，即，生物phalariaspp。和Bulinusspp.,分别。我们推导了在这些数据上拟合的非线性热响应，以参数化机理，基于过程的血吸虫病模型。然后，我们将基本繁殖数和血吸虫感染的患病率作为温度的函数。我们发现，曼氏芽孢杆菌和血吸虫的热最佳传播范围分别在23.1-27.3°C和23.6-27.9°C（95％CI）之间。我们还发现，随着人类水接触率随温度的增加，热最佳值会向更高的温度转移。我们的发现与SSA中血吸虫病患病率的广泛数据集一致。此处开发的精细非线性热响应模型表明，对于一半以上的年平均温度低于热最佳值的血吸虫病适宜地区，当前气候更合适，并且随着未来变暖传播的风险更大。
