Spatial clustering pre and post-treatment for schistosomiasis and geohelminths

项目描述（由申请人提供）：本项目的最终目标是确定不同因素在血吸虫病和土壤传播蠕虫（STH）感染和再感染中的相对贡献，以改进目前控制这些寄生虫的策略。血吸虫病和STH是广泛存在的寄生虫感染，对社会经济发展造成巨大损失。估计有20亿人受到这些寄生虫的影响。研究多重感染的程度以及它们在感染易感性和疾病结局方面相互影响的程度，对于考虑联合使用化疗和疫苗接种的控制方案非常重要。由于可用于控制的资源往往有限，了解血吸虫病在微观层面的分布对于制定针对高危人群的最佳干预策略至关重要。我们相信，空间方法可以识别宿主遗传、免疫和行为特征、环境和其他决定人群感染和疾病模式的因素之间复杂的相互作用。因此，本研究将检验3个一般假设：1)在个体、家庭和社区水平上，PZQ和阿苯达唑治疗后mansoni和STHs感染和再感染的空间分布不是随机的，而是异质性的；2)上述寄生虫的空间分布与人口统计学、免疫学、遗传、社会经济和人类行为参数有关；3)在距离潜在传播点和传播潜力点不同距离的人群和家庭中，治疗方案的影响是不同的。治疗方案后感染的地理空间聚集性与感染前的聚集性有显著不同。在检验这些假设的过程中，我们将比较治疗前和治疗后一年的个体和家庭水平的蠕虫空间分布，并分析我们已经掌握的流行率、感染强度、人口统计学、社会经济、水接触模式、遗传和免疫因素的数据。我们还将在第二次治疗2年后使用相同的方法收集与这些变量相关的数据。这项试点研究中使用的方法，包括对多种寄生虫感染和化疗干预后再感染的建模工作，可能会在其他农村地区进行试验。

DESCRIPTION (provided by applicant): This project has the ultimate goal of determining the relative contribution of different factors in infection and reinfection of schistosomiasis and soil transmitted helminths (STH) to improve current strategies for control of these parasites. Schistosomiasis and STH are widespread parasitic infections posing an enormous toll on the socioeconomic development. An estimated 2 billion people are affected by those parasites. Studies of the extent of multiple infections and the impact they have on each other in terms of both susceptibility to infection and disease outcomes are important for control programs that consider the use of chemotherapy and vaccination jointly. As resources available for control are often limited, it is essential to know the distribution of schistosomiasis at the micro-level to devise optimal intervention strategies for targeting high- risk population. We believe that a spatial approach can lead to identification of complex interactions among host genetic, immunological, and behavioral characteristics, the environment, and other factors that determine the pattern of infection and disease in human populations. Therefore the proposed project will test 3 general hypothesis: 1 )that spatial distributions of S. mansoni and STHs infections and reinfection following PZQ and albendazol treatment are not random but heterogeneous at the individual, household and community levels; 2)that spatial distribution of the above parasites is associated with demographic, immunological, genetic, socioeconomic and human behavior parameters and 3)that the treatment program will have a varying impact across groups and households located at different distances from potential transmission sites and from sited with different transmission potential. The geospatial clusters of infection after the treatment program will be significantly different from the pre-infection clusters. In the process of testing these hypothesis we will compare the spatial distribution of helminths individually and at households evels before treatment and one year after treatment and analyzed with data we already have of prevalence, ntensity of infection, demographic, socioeconomic, water contact patterns, genetic and immunological actors. We will also collect data related to those variables 2 years after the second treatment using the same methods. The approach used in this pilot study, including modeling efforts of multi-parasite infection and re-infection with a chemotherapy intervention, may be tested in other rural areas.