title: Comparison of three methods of immunization against bovine anaplasmosis: evaluation of protection afforded against field challenge exposure.
abstract: The efficacy of three immunization methods for bovine anaplasmosis was tested on 88 yearling Normandy cattle which were challenge-exposed under field conditions in an enzootic zone in Colombia, South American. A total of 30 cattle were immunized (premunized) with a presumed mild Colombian isolate of Anaplasma marginale; 29 calves were vaccinated with an attenuated A marginale of ovine origin; and 29 were exposed to a virulent A marginale stabilate of Colombian origin. Twenty-nine nonvaccinated cattle served as controls. Parasitemia, packed cell volume, body weight, and complement-fixation antibody response were monitored to determine host response to challenge exposure. The calves experienced a Babesia challenge exposure following arrival in the enzootic zone, after which a transient increase in Anaplasma parasitemia, accompanied by a decrease in packed cell volume, occurred in most of the vaccinated calves. However, neither clinical anaplasmosis nor mortality due to the disease occurred in the immunized cattle. Twenty-seven of the nonvaccinated calves had signs of clinical anaplasmosis and five (17%) died of the disease.
mesh_terms: D000712:Anaplasmosis / Q000382:microbiology / Q000517:prevention & control*; D000818:Animals; D001404:Babesiosis / Q000150:complications; D001428:Bacterial Vaccines / Q000008:administration & dosage; D001769:Blood / Q000382:microbiology; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology / Q000517:prevention & control*; D007114:Immunization / Q000662:veterinary*; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D013984:Tick Infestations / Q000150:complications / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000008:administration & dosage
chemical_list: D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated