全球气候变暖对中国血吸虫病传播影响的研究 Ⅰ.钉螺冬眠温度与越冬致死温度的测定

IMPACT OF GLOBAL WARMING ON THE TRANSMISSION OF SCHISTOSOMIASIS IN CHINA Ⅰ. THE HIBERNATION AND LETHAL TEMPERATURE OF ONCOMELANIA HUPENSIS IN LABORATORY

目的 研究气候变暖对中国大陆钉螺分布的潜在影响 ,实验测定钉螺适生性中的重要因子冬眠温度和越冬致死温度。方法 现场采集江苏省湖沼地区的湖北钉螺指名亚种 (O.hupensishupensis) ,在实验室采用模拟自然环境逐步改变温度的方法分别进行实验测定。结果 钉螺半数冬眠温度 (ET50 )为 5 .87℃ (95 %可信区间为 5 .3 2 -6.2 3℃ ) ;13℃以下温度与钉螺冬眠率间的 logistic回归方程为 :Y=10 1/(1+ e0 .83 73 0 4x-5.44 2 476) (F =3 5 7.85 4,P<0 .0 0 1)。钉螺在干燥和潮湿环境中的低温半数致死温度 (L T50 )分别为 -2 .3 4℃ (95 %可信区间为 -2 .19℃至 -2 .5 1℃ )和 -2 .72℃ (95 %可信区间为 -2 .5 4℃至 -2 .91℃ ) ,低温和钉螺死亡率间的 logistic回归方程分别为 :Y干 =10 1/(1+e1 .3 3 54 99x+3 .3 3 8748) (F =5 7.677,P<0 .0 0 1) ;Y潮 =10 1/(1+ e0 .92 1 0 3 4 x+2 .763 1 0 2 ) (F =69.866,P<0 .0 0 1)。结论 11℃以下钉螺开始出现冬眠现象 ;

Objective To determine the hibernation temperature and lethal temperature in winter of Oncomelania hupensis which are two of important indexes in the study on suitability of Oncomelania snails in order to understand the potential impact of global warming on the distribution of Oncomelania snails in China's Mainland. Methods Snails, namely Oncomelania hupensis hupensis, were collected from the marshland region in Jiangsu, and the two indexes of hibernation and lethal temperature were examined in laboratory by declining temperature progressively. Results The hibernation temperature of 50% Oncomelania snails was 5 87℃ with the 95% of confidence interval from 5 32 to 6 23℃;The logistic regression equation between temperature under 13℃ and hibernation rate of Oncomelania snails was = 101/(1+e 0 837304x-5 442476 ) (F=357 854, P<0 001). The lethal temperature of 50% Oncomelania snails was -2 34℃ in dry environment (95% confidence interral from -2 19 to -2 51℃), and -2 72℃ in wet environment (95% confidence interral from -2 54 to -2 91℃),their logistic regression egnations could be expressed in d= 101/(1+e 1 335499x+3 338748 ) in dry environment (F=57 677, P<0 001), and w= 101/(1+e 0 921034x+2 763102 ) in wet environment (F=69 866, P<0 001)?Conclusions The temperature of the beginning of Oncomelania snail hibernation is 11℃. The snail is weaker in dry environment than in wet environment in low tempreture.