不同地区 不同环境类型钉螺对日本血吸虫易感性的测定

对采自国内9省(市)37个点的钉螺以毛蚴与钉螺20:1的比例进行人工感染,测定各地钉螺对无锡地区日本血吸虫的易感性.结果在相同条件下,不同地区、不同环境类型钉螺对日本血吸虫的易感性不同,其中以上海、江西、江苏、湖北、湖南、安徽等地钉螺较易感,感染率分别为79.5%、72.1%、45.5%、43.3%、32.2%、20.7%;福建、四川钉螺为低度易感,感染率分别为3.9%和3.6%;而云南钉螺则不易感.湖沼、水网、山丘型钉螺的感染率分别为48.8%、39.1%和11.7%,三者总的来说易感性有显著差异.进一步分析显示,即使来自同一地区,但属于不同环境类型的钉螺,以及属于同一环境类型而来自不同地区的钉螺也具有不同的易感性.

SUSCEPTIBILITY OF ONCOMELANIA HUPENSIS TO SCHISTOSOMA JAPONICVM

Susceptibility of Oncomelania hupensis collected from 37 pilots in 9 provinces and imunic-ipality of mainland China to Schistosoma japonicum was studied in laboratory. The miracidia of Schistosoma japonicum from laboratory of Jiangsu Institute of Parasitic Diseases were used to infect snails with a ratio of 20 : 1 in group infection. Results showed that susceptibility of the snails from various areas and environment varied in the same laboratory condition. The snails from Shanghai municibality and Jiangxi,Hubei,Hunan,Anhuai provinces showed to be more susceptible to the parasite with the infection rate of 79. 5%, 72. 1%, 45. 5% ,43. 3%, 32. 2% and 20. 7% respectively,while snails from Fuojian and Sichuan showed lower infection rate of 3. 9% and 3. 6% respectively, and the snails from Yunnan were insusceptible. 48. 8%,39. 1% and 11. 7% of snails from three types of environment (lake, plain and mountainous regions) were infected with Schistosoma japonicum respectively,and showed singnifi-cant difference (P<0. 01). The results of further analysis showed that different susceptibility existed in snails from same area but with different environment or snails of same environment from different areas. It may be caused by genetic variation of Oncomelania snails in various environment in a long term.