Vaccine induced resistance against E. granulosus in dogs

Xinjiang Veterinary Research Institute, Urumqi

Investigators

Linked publications & trials

Abstract

Hydatid disease (echinococcosis) is a cosmopolitan zoonosis caused by the tape-worm Echinococcus granulosus in the intestine of dogs. The disease is important not only in terms of public health, but also for economic development in poorer endemic areas, such as North-western China. Despite the substantial efforts made to control hydatid disease, there is a clear need for new advances in its prevention and control. Dogs are pivotal in E. granulosus transmission and we contend that interruption of the parasite life cycle in the definitive host provides a very acceptable and cost-effective vaccination strategy to complement the Eg95 vaccine currently being developed by Australian researchers that targets infection in the intermediate host. Using differential display, we have identified products of a family of genes (the EgM family) associated with adult worm development and egg production that, in a pilot vaccine trial using Freunds adjuvant, provided a high level of vaccine efficacy. We now need to repeat these experiments using more acceptable adjuvants for vaccination of dogs. We will use saponin adjuvant, and Immunostimulating complexs (ISCOMs) to stimulate dog mucosal immune responses, which are suggested to play a major role in protection against gastric parasites. We will vaccinate dogs to establish a method to stimulate mucosal immune responses with the recombinant proteins. We will undertake more rigorous vaccine/challenge trials on dogs with these recombinant proteins expressed in bacteria. We will determine whether the protective efficacy established previously is maintained and whether mucosal immune responses can play a role in protection of dogs from E. granulosus infection by vaccination with the recombinant proteins. We will test humoral and cellular responses generated during vaccination to determine possible correlations of the immune parameters with protection.