Determinants of Schistosomiasis Re-emergence

描述(申请人提供)：我们在中国开展的日本血吸虫感染传播与控制研究的长期目标是开发设计特定地点控制方案的方法，以实现可持续的传播终止。最近在以前受控制的县再次出现传播促使我们提出这项建议，其中我们扩展了我们的目标，包括对重新出现的决定因素的了解，这将为监测方案的设计提供信息，以便及早发现并将再次出现的规模和影响降至最低。我们研究的目的是：1.检验由两个村级因素驱动的假说：内部潜力(一个村庄固有的支持传播的能力，包括钉螺密度、人和动物宿主以及农业实践)和连通性(与从流行地区引入寄生虫有关的因素)，这可以从现有的历史记录和遥感获得；2.使用病例对照研究，检验个人水平的村内和村外水接触可以预测重新出现的村庄的初始感染的假说；3.利用突发传播的随机模型，探讨偶发事件对有效监控系统设计的影响。与公共卫生的相关性：这项研究与公共卫生相关，因为它将增加我们对与传染病复发相关的因素的了解。通过这种理解，可以开发更好的监测方法来保护公众健康。

DESCRIPTION (provided by applicant): The broad long-term objectives of our research on the transmission and control of Schistosoma japonicum infections in China have been to develop methods for the design of site-specific control programs to achieve the sustainable cessation of transmission. The recent re-emergence of transmission in formerly controlled counties has prompted this proposal, in which we extend our objectives to include an understanding of the determinants of re-emergence, which will inform the design of surveillance programs for the early detection and minimization of the scale and impact of re-emergence. The aims of our research are to 1. Test the hypothesis that re-emergence is driven by two village-level factors: internal potential (a village's inherent ability to support transmission that includes snail density, human and animal hosts, and agricultural practices) and connectivity (factors related to the introduction of parasites from endemic areas), which can be obtained from existing historical records and remote sensing; 2. Using a case-control study, test the hypothesis that individual-level within-village and outside-village water contact is predictive of the initial infections in re-emergent villages; and 3. Utilize a stochastic model of re-emergent transmission to explore the effect of chance events on the design of an effective surveillance system. Relevance to public health: This research is relevant to public health, in that it will increase our knowledge of the factors related to infectious disease re-emergence. Through this understanding, better surveillance approaches can be developed to protect public health.