内蒙古西伯利亚棘球绦虫和多房棘球绦虫泡状蚴在小白鼠发育成熟的比较

COMPARISON OBSERVATION ON THE MATURE ALVEOLAR OF ECHINOCOCUS SIBIRICENSIS AND ECHINOCOCCUS MULTILOCULARIS IN THE EXPERIMENTALLY INFECTED WHITE MICE

本文报道人兽共患的泡状肝包虫病原,西伯利亚棘球绦虫Echinococcus sibiricensis(Rausch and Schiller,1954)泡状蚴和多房棘球绦虫Echinococcus multilocularis(Leuckart,1863)泡状蚴在KM株小白鼠发育成熟过程比较观察的结果。此两虫种泡状蚴的发育成熟过程仍然和它们早期发育的规律(唐崇惕等,2001)相同。虽然它们成熟的泡囊都被着生在网状结构中的许多原头节所充满,但是在多房棘球绦虫9-14个月的泡状蚴,仍然可以见到它们的原头节和网状结构都是起源于泡囊囊壁内表面的胚细胞层,并且始终保持与该层的联系。而西伯利亚棘球绦虫泡状蚴在鼠肺脏或肝脏的各泡囊中的原头节和网状结构是由可移动的胚细胞团发育生成,它们与泡囊囊壁没有如前者样的联系。西伯利亚棘球泡状蚴在各别小白鼠肝脏也能发育成熟,但不正常,宿主反应异常强烈。

The alveolar echinococcus is one of the most dangerous worm parasites in man. Rausch and Schiller reported a new species, Echinococcus sibiricensis n. sp. from arctic fox, Alopex logopus, on St. Lawrence Island of Alaska, USA. According to the view of Vogel, the sibiricensis form is only a geographical race or subspecies of Europe Echinococcus multilocularis. So far, the two names, Echinococcus multilocularis multilocularis and Echinococcus multilocularis sibiricensis, existed in many references and text books. We have found the adults of Echinococcus sibiricensis and Echinococcus multilocularis from sand foxes, Vulpes corsac and their larval stages (alveolar echinococcus) from field voles, Microtus brandti in the Hulunbeier Pasture of Inner Mongolia, northeastern China in 1985 and 1998 - 1999. Two types of metacestodes with quite different styles of early development of E. sibiricensis and E. multilocularis were found from field voles and laboratory experimental white mice. As one characteristic of alveolar E. multilocularis , the capsules are produced by the exogenous budding of germinal cell layer together with cyst wall. The proto-scoleces grow from germinal cells on germinal cell layer. The peduncles of early protoscoleces attached to the germinal cell layer on the inner surface of capsule wall (Plate I, Figs. 1~2). Some protoscoleces in reticular structure were linked with the inner surface of capsule wall ( Plate I, Fig. 3) in livers of mice in 9. 5th month postinfection. In 14th month old alveolar multilocularis, large number of mature protoscoleces in reticular structure were still linked to the inner surface of capsule wall (Plate I, Figs. 4 -8). The cavities of some capsules were filled with protoscoleces in meshes of reticular structure which were also linked around with the inner surface of capsule wall ( Plate I, Fig. 9). The superficial surface of livers of positive field voles and experimental mice never showed any hyper-emic phenomenon. The superficial surfaces of livers and lungs of positive field voles and experimental mice infected with alveolar E. sibiricensis were highly hyperemic. The metacestodes of E. sibiricensis composed of mother cyst, undifferenti-ated embryonic cysts and small brood capsules. Cavities of all cysts were fully filled with germinal cell masses. Host reaction appeared to be very strong, all cysts were surrounded by thick connective tissue and dense leukocytes (Plate Ⅱ, Fig. 10) . All alveolar vesicles were found located in lungs tissue of experimental mice. Large germinal cell masses metastasized out from undifferentiated embryonic cysts into host lung tissue, where germinal cell masses developed into accumulation of early protoscoleces (Plate Ⅱ, Figs. 11 - 12). Early protoscoleces of alveolar E. sibiricensis were seen earliest in mice lung tissues on 101 - 104th days after infection. Many small capsules in different sizes and different shapes containing mature protoscoleces and reticular structure (Plate Ⅱ, Figs. 13 - 15) were found in lungs of mice in 9th month after infection. Only in one experimental mouse infected with alveolar E. sibiricensis in 8. 5th month postinfection, both its lung and liver existed alveolar cysts; the capsules in liver were surrounded by very thick connective tissue of the host, and there were some protoscoleces in their cavities (Plate Ⅱ, Figs. 16-18).