Babesiosis

Abstract

Babesiosis is a tick-transmitted disease of cattle manifested by anemia, occasional hemoglobinuria, and the appearance of infecting protozoa in the host erythrocytes. Various species of babesia are known to infect cattle, however, the most economically important are those caused by Babesia bovis (Syn. argentina) and B. bigemina. Babesiosis is presently considered as one of the most important constraints in production of cattle in most regions with tropical and semitropical climates. The course of infection depends on the species of babesia involved. Animals infected with virulent babesias usually need chemotherapy before acquired immunity develops. Babesia infection commonly persists for long periods of time. Maintenance of immunity is not dependent on the presence of the parasite. Antibody titers detected by serologic tests do not always relate to levels of protective immunity. Humoral-antibody protection, however, has been demonstrated by passive and active immunization. The role of cell mediated immunity (CMI) in protection has not been clearly documented. Active immunization against babesiosis has been achieved with virulent strains, irradiated parasites and inactivated parasites in adjuvant.

A scientific breakthrough in the study of babesiosis was recently achieved by development of cell cultural systems for continuous propagation of B. bovis. Antigens derived from these cultures have been proven effective and safe immunogens. Using this new technique, vaccines for prevention of bovine babesiosis should be commercially available in the near future.