大雪对洞庭湖区钉螺生存影响的现场观察

Field observation on survival of Oncomelania hupensis in Dongting Lake area under a long period of snow weather

目的探讨大雪低温气候条件下,洞庭湖区日本血吸虫中间宿主湖北钉螺的生存状态,为血吸虫病研究和控制提供基础信息。方法选择湖南省岳阳市君山公园前滩为现场,2008年春季大雪前后采用系统抽样法查螺,分框记数,解剖鉴定钉螺死活、感染性、雌雄构成情况,计算活螺平均密度、活螺框出现率、钉螺死亡率、钉螺雌雄构成等指标。结果钉螺活螺平均密度大雪冰冻天气后降低45.68%(Z=-5.99,P<0.01),活螺框出现率降低32.18%(χ2=18.04,P<0.01),钉螺死亡率上升27.68%(Z=-12.67,P<0.01),高达88.80%,钉螺雌雄构成无明显变化。结论持续大雪冰冻天气使钉螺活螺密度降低,死亡率升高,但密度仍维持较高水平。

Objective To understand the survival of Oncomelania hupensis under a long period of snow weather so as to provide the basic information for the research and control of schistosomiasis. Methods A marshland close to Junshan Park in Yueyang City, Hunan Province was selected as the pilot. （3. hupensis snails were investigated by using the systematic sampling method, and the number of the snails were surveyed and the sex, survival status and infection of the snails were indentified by using the dissection method. Results The average density of living snails dropped by 45. 68% （Z= -5. 99, P〈0.01）, the occurrence rate of the frame with living snails reduced by 32. 18% （X2= 18. 04,P〈0.01）, while the mortality rate increased by 27. 68% （Z= - 12. 67, P〈0.01） and the mortality rate amounted to 88. 80%, but no significant changes in the sexual ratio was observed. Conclusions The long period of snow weather with low temperature reduces the density of living snails and increases the mortality rate of O. hupensis, while the density of snails is still comparatively high.