Immunization of lambs with whole body Echinococcus granulosus

We conducted this study to determine the level of immunity after vaccination of lambs with whole bodyEchinococcus granulosus. To do so, 200 mature E. granulosus parasites, which were kept in 10% formalinefor 8 months, were obtained from the Department of Parasitology, School of Veterinary Medicine, FerdowsiUniversity of Mashhad. The soluble protein of the parasite was prepared. The sample was homogenized in ablender, sonicated on ice and then centrifugated for 15 min at 10,000 g. Final yield was kept at -20ºC untilused. Eight 4–6-month-old lambs of mixed sex, were divided into 2 equal groups; each lamb in the test groupwas vaccinated subcutaneously in the neck with 2 ml of the vaccine (1 mg of whole body of E. granulosusprotein dissolved in 1 ml of PBS plus 1 ml of Freund’s complete adjuvant (FCA)). The control lambs werevaccinated only with adjuvant in PBS. Lambs were re-vaccinated four weeks after the first vaccination withthe same preparation except that FCA was replaced by Freund’s incomplete adjuvant (FIA). Three weekslater, each lamb was administered a challenge infection dose of 2000 protoscolices intraperitoneally and 10adult E. granulosus. After 7 months, all lambs were killed and examined for hydatid cysts. We found twocysts in the liver and and one in the lung of only one of the vaccinated lambs. The number of cysts invaccinated lambs were significantly lower than that in the control group (P