IMMUNOLOGICAL RESPONSES OF MAMMALIAN HOST AGAINST TAPEWORM INFECTIONS .4. SPECIES SPECIFICITY OF HEXACANTH EMBRYOS IN PROTECTING SHEEP AGAINST ECHINOCOCCUS GRANULOSUS

  • 1 January 1966
    • journal article
    • research article
    • Vol. 11  (4) , 325-+
Abstract
Eighty lambs were divided into 4 groups, each comprising 20 animals. Half the lambs in each group were vaccinated with viable eggs and half with the activated embryos of Echinococcus granulosus, Taenia hydatigena, T. ovis or T. pisiformis. These lambs together with 10 control animals were subsequently challenged with eggs of E. granulosus. Only a few hydatid cysts were established from the challenge infection in the lambs immunized with the homologous eggs or embryos. Only one acephalocyst in one animal survived. The metabolism of this cyst was of a low order compared with that of most of those in the controls. Hydatid cysts were established from the challenge infection almost as frequently in the animals vaccinated with eggs or embryos of the sheep metacestodes T. hydatigena and T. ovis, as in the controls. Fluid accumulated in only a few hydatid cysts from the challenge infection in those sheep vaccinated with the activated embryos of these heterologous species. The injection of viable eggs or activated embryos of the rabbit metacestode T. pisiformis induced no resistance to the establishment or to the survival of the challenge infection of E. granulosus.