异育银鲫寄生指环虫的流行病学及其致病的生态机制

随着异育银鲫在我国的大规模推广和高密度养殖，指环虫病的发生日益频繁和严重，已成为我国淡水养殖鱼类危害最严重的寄生虫病之一。本项目将调查异育银鲫寄生指环虫的种类和季节动态，研究指环虫的产卵、孵化和感染条件，阐明指环虫的流行病学规律，并利用一种常见种类，建立指环虫的人工感染系统；运用该系统，研究异育银鲫养殖密度、水体理化参数和环境胁迫因子对指环虫感染的影响，并结合鱼体的非特异性免疫参数和组织病理学，阐明指环虫病暴发的条件及其致病的生态机制；最终将根据指环虫的流行病学及其致病的生态机制，提出生态防控策略，减少化学药物对环境的污染和对食品安全的影响。此外，指环虫人工感染系统的建立还将为指环虫病防治新型环保药物的筛选提供平台。

The occurrence of Dactylogyriasis became more and more frequent and serious because of the intensive aquaculture. It was now one of the most important parasitic diseases in freshwater stocked fishery. In the present study the species of Dactylogyrus and their seasonal dynamics will be investigated in the allogynogenetic crucian carp (Carassius auratus gibelio). Effects of environmental factors on oviposition, egg hatching and oncomiracidia will be studied. Based on the results, epidemiology of the Dactylogyriasis will be illustrated, and artificial infection system of the Dactylogyrus will be established. By utilization of the artificial infection system, effects of the fish population density, physicochemical factors of waters and environmental stress on infection of the Dactylogyrus will be discussed. Combined the nonspecific immunity and histopathology, conditions and ecological mechanisms of the outbreak of Dactylogyriasis will be clarified. In the end, strategies of ecological defence and control will be drawn up according to the epidemiology and ecological mechanisms of Dactylogyriasis, which can reduce the effects on environment polution and food security caused by chemical medicine. Furthermore, the artificial infection system can also provide research platform for screening of the environment friendly medicine against the Dactylogyriasis.