Cystic echinococcosis: Development of an intermediate host rabbit model for using in vaccination studies

The aims of this study were an establishment of the domestic rabbit as an intermediate host for cystic echinococcosis (CE) and to evaluate the potency of the crude germinal layer and the protoscoleces antigens to protect against the CE. Firstly; Two groups of white Newzeland rabbits were infected orally either by 5000 active oncospheres or viable protoscoleces separately. After 20 weeks, the slaughtered rabbits showed the presence of hydatid cysts at different internal organs. Molecular detection of the resulted cysts was conducted. Secondly; 27 rabbits were divided into nine groups (n = 3). Groups 1 and 2 were immunized with the crude germinal layer antigen while the groups 3 and 4 were immunized with the crude protoscoleces antigen. Groups 5 and 6 received the adjuvant mineral oil. Groups 7 and 8 were used as positive control. The last 9 group was kept as a negative control. The obtained results showed a significant high protection percentage of 83.4% and high antibody titer was recorded in groups that received the crude germinal layer antigen comparing with the groups that immunized with the crude protoscoleces antigen as their protection percentage was 66.7% with lower IgG response. In conclusion, the domestic rabbits could be used as a laboratory model for CE. Developing of the germinal layer antigen is more immunogenic than the protoscoleces one and could be used as a promising vaccine. Attention should be directed towards the existing rabbit in the environment adjacent to infected dogs as it could be a part of Echinococcus life cycle.