Development and deployment of a vaccine against babesiosis
Babesiosis is a disease that affects cattle, water buffaloes, and African buffaloes. It is caused by babesia bovis, a parasite transmitted by ticks. This parasite hides in red blood cells and evades immune responses, resulting in a persistent infection that often results in death. Babesiosis occurs in many parts of the world where the ticks are present, including Africa and Asia, and its prevalence and incidence are often underestimated. Economic studies have estimated annual losses in India and Tanzania at US$57 million and US$46 million respectively. Current vaccines against babesiosis consist of live attenuated pathogens produced from the blood of infected animals, although parasites grown in the lab are also available as vaccines in some parts of Latin America. While vaccination of young animals results in solid lifelong immunity, current vaccines are not safe as they may cause adult animals to become infectious, may be contaminated with other pathogens, or may cause hypersensitivity reactions.
This project aims to generate a dual vaccine that is designed to block parasite infection of host capillary blood vessels and transmission by tick vectors. Using cutting-edge bioinformatics and experimental platforms, babesia bovis red blood cell surface-exposed proteins will be tested for their ability to induce antibodies that block adhesion of infected blood cells to blood vessel walls, and hence prevent acute disease. Similarly, bioinformatic tools will be used to identify conserved babesia bovis candidate antigens exclusively expressed in the tick stages of the life cycle of the parasite. A combination of these two sets of antigens will then be developed into a vaccine and used in a disease-challenge study in cattle. Thus a dual-purpose vaccine with capacity to prevent clinical disease and babesia transmission will be developed and will have potential for refinement into a commercial vaccine.
This project is a collaboration between the United States Department of Agriculture and Australia-based Monash University. The U.S.-based Washington State University Pullman and the Bioscience East and Central Africa (BecA)-ILRI Hub in Nairobi, Kenya will also participate as sub-grantees.
This project is funded through the Livestock Vaccine Innovation Fund, a partnership between the Bill and Melinda Gates Foundation, Global Affairs Canada and IDRC. It represents a joint investment of CA$57 million over five years to support the development, production, and commercialization of innovative vaccines against priority livestock diseases in sub-Saharan Africa, South Asia, and Southeast Asia.