ABSTRACT
Cattle immunization studies utilizing blood-derived nonliving Babesia antigens and protection to clinical infection after elimination of the agent from carrier animals by chemotherapy indicated that the sterile immunization approach to vaccine development against babesiosis is possible. Other research efforts explored the use of tick-derived preinfectious Babesia forms as a means of inducing protective immunity against bovine babesiosis. Among several disadvantages, there are two major difficulties with the use of infected cattle-derived blood for the preparation of anti-Babesia vaccines. The first obvious difficulty is that the method is too laborious and costly for mass vaccine production. The second difficulty is the development of antibodies to isoerythrocytic antigens in vaccinated animals. Live Babesia vaccines are by no means safe for cattle. Use of live, multistrain vaccines for the control of bovine babesiosis has been reported in Australia and South Africa. Culture-derived Babesia exoantigens have proved useful and effective in protecting highly susceptible cattle against babesiosis.
