内蒙古东部新巴尔虎右旗泡状肝包虫病原种类及流行学调查

The Species and Bioepidemiology of Alveolar Echinococcus in Xinbaerhu West County, Eastern Inner Mongolia

报道 1998～ 1999年在内蒙古东部呼伦贝尔盟新巴尔虎右旗 3个乡草场进行人兽共患泡状蚴病病原调查研究的结果 .沙狐 (Vulp es corsac)和布氏田鼠 (Microtus brandti)分别感染有多种泡状肝包虫的成虫和幼虫期 .其中有西伯利亚棘球绦虫 (Echinococcus sibiricensis)和多房棘球绦虫(Echinococcus multilocularis) ,并经人工感染试验证实它门是具不同发生学的两个独立种类 .布氏田鼠的泡状蚴平均感染率高达 2 %～ 19.0 2 % ,在不同地点和不同季节它们的感染率有所差别 .同时 ,在该草原布氏田鼠尚发现与其他棘球蚴不同的呼伦贝尔泡状蚴新种 (Alveolaris hulunbeierensis sp.nov.)

This communication reports the results of a survey on the bioepidemiology of alveolar echinococcus on grasslands of Xinbaerhu West County in Hulunbeier Pasture, Eastern Inner Mongolia ; and the results of experimental infections on laboratory white mice with adults of Echinococcus multilocularis (Leuckart, 1863) and Echinococcus sibiricensis Rausch and Schiller, 1954 collected from Vulpes corsac captured from West County. Three species of alveolar echinococcus were found from field voles, Microtus brandti in grasslands of Xinbaerhu West County. The three species of alveolar echinococcus were metacestodes of E. sibiricensis (89.4% in positive voles) and E. multilocularis (8.77%), and Alveolaris hulunbeierensis n. sp.(1.76%). These 3 alveolar echinococcus not only differed in the structure of alveolar cysts, but also in the development pattern. They showed different characteristics of separate species. In the present investigation, of the 647 Microtus brandti captured from three villages of Xinbaerhu West County, 67 (9.94%) were found to be infected with alveolar echinococcus. The infection rates were different in different villages, as follows: Eerdun Village 7.59% (35/461); Hulun Village 19.02% (31/163); Baogede Village 2.0% (1/50). Infection rates in Spring (April) 12.61%(15/119)~23.68%(9/38) and in Autumn (Sept.) 17.60% (22/125)~ 6.25 % (1/16) were higher than that in Summer (July) 5.85% (20/342)~0% (0/34). 36 Vulpes corsac , 6 Vulpes vulpes and 9 Canis lupus were captured from grasslands of Xinbaerhu West County and were examined. Adults of Echinococcus granulosus were found from 3 (33.3%) of 9 Canis lupus , Adults of Echinococcus sibiricensis were found from 2 (5.56%) of 36 Vulpes corsac, one of the 2 positive corsac foxes was mixed infected with the adults of Echinococcus multilocularis (2.76%). Under experimental condition, 203 white mice (Kunmin strain) were orally infected with both gravid proglottids of E. sibiricensis and E. multilocularis respectively and mixedly, which were collected from Vulpes corsac captured from Xinbaerhu West County. The alveolar cysts of E. sibiricensis were found from lungs of mice; many germinal cells masses existed in undiferrentiated embryonal cysts cavities of parasite, they metastasized off cysts into lung tissue of host to form brood capsules and protoscolice which manifested in 9 th month postinfection; host reaction strong. While the alveolar cysts of E. multilocularis developed in livers of white mice; germinal cells layer which attached on inner surface of cysts wall proliferated by budding pattern to form new vesicles; the protoscolice which grew from germinal cells layer manifested in 5 th and 6 th months postinfection; host reaction slight. The larval stages of the two species Echinococcus in experimentally infected white mice were similar to those in naturally infected Microtus brandti .