日本血吸虫幼虫在钉螺体内发育有效积温的研究

Investigation on effectively growing degree days of cercaria of Schistosoma japonicum developing in snail

目的 研究日本血吸虫幼虫在钉螺体内发育成熟所需的热量 (发育有效积温 )。方法 现场采集无血吸虫感染的钉螺 ,以钉螺∶毛蚴为 1∶2 0比例进行实验感染 ,感染后常规饲养 ,以逸蚴法确定感染性钉螺 ,根据变温动物发育积温和有效积温的计算公式 (Q =∑Tn、K =N(T -C) ) ,计算血吸虫在钉螺体内发育的尾蚴开放积温和发育有效积温。结果 在 2 1～30℃之间 ,血吸虫在钉螺体内尾蚴开放的最低积温为 12 0 0日度 ,最高积温为 3480日度 ,平均积温为 2 2 0 2 75± 378 86日度。血吸虫在钉螺体内的发育有效积温常数为 84 2 91日度 (95 %可信区间为 6 99 2 8～ 986 5 4日度 )。结论 日本血吸虫在钉螺体内要完成发育至成熟的尾蚴 ,所需的有效积温 (环境温度在 15 17℃以上的累积温度 )必须达到 84 2 91日度。

Aim To investigate the energy (or growing degree days) needed for development of cercaria of Schistosoma japonicum in Oncomelania snail.Methods The uninfected snails were collected from the field,and exposed to the cercaria of Schistosoma japonicum by the ratio of 1∶20.Based on the data from the experiment,the accumulated temperature and effective growing degree days of cercaria developing in snail were estimated by the formula of Q=∑T n、K=N(T-C).Results At the environmental temperature at 21-30℃,the average accumulate temperature for cercaria mature was 2202.75±378.86 degree days, ranging from 1200 as the lowest and 3480 as the highest.While the effectively growing degree days of cercaria developing in Oncomelania snail was 842.91 degree days (the 95% confidence ranging from 699.28-986.54 degree days).Conclusion The effectively growing degree days when temperature over 15.17℃ for cercaria developing maturely in snail should be over 842.91 degree days.