Milner Fabio Augusto, Zhao Ruijun
Department of Mathematics, Purdue University, West Lafayette, IN 47907-2067, USA.
Math Biosci Eng. 2008 Jul;5(3):505-22. doi: 10.3934/mbe.2008.5.505.
It has been observed in several settings that schistosomiasis is less prevalent in segments of river with fast current than in those with slow current. Some believe that this can be attributed to flush-away of intermediate host snails. However, free-swimming parasite larvae are very active in searching for suitable hosts, which indicates that the flush-away of larvae may also be very important. In this paper, the authors establish a model with spatial structure that characterizes the density change of parasites following the flush-away of larvae. It is shown that the reproductive number, which is an indicator of prevalence of parasitism, is a decreasing function of the river current velocity. Moreover, numerical simulations suggest that the mean parasite load is low when the velocity of river current flow is sufficiently high.
在多个地区都观察到，与水流缓慢的河段相比，血吸虫病在水流湍急的河段中发病率较低。一些人认为，这可能归因于中间宿主蜗牛被冲走。然而，自由游动的寄生虫幼虫在寻找合适宿主方面非常活跃，这表明幼虫被冲走也可能非常重要。在本文中，作者建立了一个具有空间结构的模型，该模型描述了幼虫被冲走后寄生虫密度的变化。结果表明，作为寄生虫感染率指标的繁殖数是河流流速的递减函数。此外，数值模拟表明，当河流流速足够高时，平均寄生虫负荷较低。
