Experimental vaccination of sheep against hydatid cyst using EG95 recombinant vaccine

Vaccination of livestock with effective vaccine could be one of the control methods for hydatid cyst. In this study a new recombinant vaccine (Eg95) from New Zealand was prepared and used. Thirty health sheep from the same race and identical age and sex were selected. There was no history of any past vaccination or disease in selected animals. Animals were randomly categorized to four groups. One group including ten sheep received two times vaccination and each time 50 microgram with two weeks interval. Another group (10 sheep) received physiological saline without vaccine. Five weeks after second vaccination both groups were challenged with 3500 freshly Echinococcus granulosus (Iran isolate, dog/sheep cycle) eggs intraruminally. Animals, in third and fourth groups, received vaccine and physiological saline respectively. Third and fourth groups did not challenge and kept for vaccine adverse effects or natural infection control. Anti-Eg95 antibody titer was evaluated with ELISA before and two weeks after each vaccination. Optical density (OD) rates for all groups were less than 0.1 before vaccination. A 40 fold increase in OD rates of vaccinated groups was seen 2 weeks after second vaccination. Animals under the study were fully surveyed. Results indicated 98% protection in vaccinated group when they were necropsied 12 months after challenge. The EG95 vaccine can be produced on an industrial scale and can be further use for clinical trial in Iran.