水牛是我国血吸虫病疫区最重要的保虫宿主，水牛血吸虫病防治在我国血吸虫病防控上具有重要意义。疫区幼年水牛血吸虫感染率显著高于成年水牛，人工感染实验证明幼年水牛感染血吸虫的后期虫体可以逐渐消亡，且感染/治疗的水牛对血吸虫再感染具有抗性。本项研究拟通过感染/治疗方式构建水牛抗再感染模型，详细观察再感染组诱导过程中以及再感染组和对照组之间粪便虫卵数、粪便毛蚴孵化数、解剖收集的虫体数等方面的差异，阐明水牛抗再感染现象产生过程，量化抗再感染程度；从再感染组和对照组血吸虫在形态学、基因表达、虫体细胞凋亡等方面系统分析再感染血吸虫“受伤”程度和原因；分析再感染组和对照组水牛抗血吸虫特异性同型抗体、细胞因子、靶抗原、免疫反应类型等方面的差异，揭示水牛抗抗再感染相关的免疫机制。本研究可为研制抗血吸虫疫苗、寻找治疗药物靶标、制定血吸虫防治对策提供科学依据。

Buffalo is one of the most important reservoir hosts in the Schistosomiasis japonicum endemic area of China. Due to their involvement in human schistosomiasis transmission, water buffaloes are of significant public health concern. In our previous studies, we found that the prevalence of S. japonicum infections in juvenile buffaloes was significantly higher than that in adults. In artificial infecting experiments, it was also observed that the worms in yang buffaloes were gradually cleared in the period following S. japonicum infection and the infected/cured buffaloes have resistance to post-treatment reinfection. In this project, the level and molecular mechanisms of the resistance to post-treatment reinfection in buffaloes will be studied. The process and level will be illuminated through investigating the diffences of the feces egg number, egg hatching, worm burden and liver egg burden during the inducement course of reinfection group and between the reinfection group and control group (first infection). Than, the differences in morphology, gene expression and apoptosis of parasite,specific antibody isotype responses, cytokines，target antigens and immune response types of the host will be compared between reinfection and control groups. The results obtained here will illustrate the molecular mechanisms of the resistance to post-treatment reinfection in buffaloes, provide new idea for development of anti-schistosomiasis vaccine and screening of the new drug targets, as well as offering scientific basis for making prevention tactics of schistosomiasis.