Studies on genetic constraints to protective immunity in cattle

• Animal Disease Research Institute, Tanzania
• Onderstepoort Veterinary Laboratory, South Africa
• National Veterinary Research Centre, Kenya
• Department of Veterinary Services, Zimbabwe
• Queensland Department of Primary Industries, Australia

The failure of a proportion of cattle to respond to available vaccines against tick-borne diseases (TBD) is a fundamental hindrance to effective control of these diseases. Development of more efficacious vaccines in the future will require clarification of the mechanisms responsible for this problem. Effective implementation of current and future vaccines is presently constrained by inadequate diagnostics for the identification and differentiation of parasite-specific immune mechanisms in responder and non-responder cattle vaccinated with live babesia strains. Immunogenetic influences in these populations on the outcome of vaccination will be examined using a class ii MHC-typing technology developed at ILRI. In addition, Australian Babesia-specific monoclonal antibodies will be used to screen expression libraries at ILRI in order to develop more effective specific diagnostic tests for Babesia bigemina. DNA-based protocols developed in Australia to differentiate Anaplasma species and strains will be transferred to ILRI for future applications in Africa. The project will necessitate the appointment of a technician to accomplish the immunogenic component at ILRI. These methodologies and reagents will advance the development of integrated control strategies for tick borne diseases in sub-Saharan Africa and Australia and enhance the capacity of developing countries to assess the impact of these diseases on the productivity of their livestock sectors.