ECOLOGY AND TRANSMISSION OF S.JAPONICUM: PHILIPPINES

本提案的目的是发展一个动态模型的影响，由于水稻种植的日本血吸虫在菲律宾的流行地区的传播的人为变化。该模型将包括几个物种，他们的人口生物学和行为，包括人类，蜗牛和动物水库宿主的S。山茱萸我们定义了水稻种植，其空间和时间变化及其对人类S的物理，水文和动物决定因素的多重影响。日本血吸虫感染是人为环境变化。该模式将允许预测的潜在影响，人为环境变化所产生的变化，水稻种植随着时间和空间的传播上的S。japonicum对人类水稻种植因素包括：水稻种植方法、农业扩展和集约化的变化;驯养动物数量、传播行为和管理方法;水的使用和管理方法。发展血吸虫病传播给人类的可推广的预测生态模型是正在进行的努力，以开发成本效益和可接受的疾病控制策略的一个基本组成部分。目前还没有日本血吸虫的已发表模型，尽管对受感染的人进行了20年的治疗，但日本血吸虫在菲律宾和中国仍然是地方病。在最初的12-18个月期间确定几个地点的传播平衡条件后，并利用过去40年来人类、蜗牛和动物感染的现存数据，我们将建立一个S.山茱萸然后我们将治愈每个地点的所有人，并观察S的发病率和强度。日本血吸虫感染人类超过18个月。这将允许进行统计分析，以确定特定传播因素与人类感染结果的关系。这也将允许更准确地构建一个年龄结构，人口动态模型的S。日本血吸虫病传播具有改进的可预测性和可推广性。

The objective of this proposal is the development of a dynamic model of the influence of anthropogenic changes due to rice farming on the transmission of Schistosoma japonicum in the endemic areas of The Philippines. The model will include several species, their population biology and behavior, including humans, snails and animal reservoir hosts of S. japonicum. We define rice farming, its spatial and temporal variation and its multiple impacts on physical, hydrologic and animal determinants of human S. japonicum infection as anthropogenic environmental change. The model will allow the prediction of the potential effects of anthropogenic environmental changes stemming from variation in rice farming over time and space on the transmission of S. japonicum to humans. Rice farming factors include: variation in rice farming practices, agricultural expansion and intensification; domesticated animal numbers, transmission behaviors and management practices; water use and management practices. Developing generalizable predictive ecological models of schistosomiasis transmission to humans is a fundamental component of the ongoing effort to develop cost-effective and acceptable disease control strategies. There are at present no published models for S.japonicum, which remains endemic in The Philippines and China despite 20 years of treatment of infected humans. After an initial 12-18 month period of determining the equilibrium conditions of transmission in several sites, and use of extant data from the last 40 years on human, snail and animal infection we will develop a dynamic transmission model of S. japonicum. We will then cure all humans in each site and observe the incidence rate and intensity of S. japonicum infection in humans over 18 months. This will permit statistical analyses to determine the relationships of specific transmission factors to the outcome of human infection. It will also allow more accurate construction of an age- structured, population dynamic model of S. japonicum transmission with improved predictabilty and generalizability.