Anderson R M, May R M
Parasitology. 1979 Aug;79(1):63-94. doi: 10.1017/s0031182000051982.
The paper draws together a large and scattered body of empirical evidence concerning the prevalence of snail infection with schistosome parasites in field situations, the duration of the latent period of infection in snails (and its dependence on temperature), and the mortality rates of infected and uninfected snails in field and laboratory conditions. A review and synthesis of quantitative data on the population biology of schistosome infections within the molluscan host is attempted and observed patterns of infection are compared with predictions of a schistosomiasis model developed by May (1977) which incorporates differential snail mortality (between infected and uninfected snails) and latent periods of infection. It is suggested that the low levels of prevalence within snail populations in endemic areas of schistosomiasis are closely associated with high rates of infected snail mortality and the duration of the latent period of infection within the mollusc. In certain instances, the expected life-span of an infected snail may be less than the duration of the latent period of infection. Such patterns generate very low levels of parasite prevalence. A new age prevalence model for schistosome infections within snail populations is developed and its predictions compared with observed patterns. The implications of this study of observed and predicted patterns of snail infection within molluscan populations are discussed in relation to the overall transmission dynamics of schistosomiasis.
本文汇集了大量分散的实证证据，这些证据涉及野外环境中蜗牛感染血吸虫寄生虫的流行情况、蜗牛感染潜伏期的时长（及其对温度的依赖性），以及野外和实验室条件下受感染和未受感染蜗牛的死亡率。本文尝试对软体动物宿主体内血吸虫感染种群生物学的定量数据进行综述和综合分析，并将观察到的感染模式与梅（1977年）开发的血吸虫病模型的预测结果进行比较，该模型纳入了不同的蜗牛死亡率（受感染和未受感染蜗牛之间）以及感染潜伏期。研究表明，血吸虫病流行地区蜗牛种群中低感染率与受感染蜗牛的高死亡率以及软体动物体内感染潜伏期的时长密切相关。在某些情况下，受感染蜗牛的预期寿命可能短于感染潜伏期。这种模式导致寄生虫感染率极低。本文开发了一种新的蜗牛种群内血吸虫感染年龄流行模型，并将其预测结果与观察到的模式进行比较。本文结合血吸虫病的总体传播动态，讨论了对软体动物种群中蜗牛感染观察到的和预测的模式进行研究的意义。
