title: Blocking Babesia bovis vaccine reactions of dairy cattle in milk.
abstract: The use of 1.16 mg/kg (one third) of the recommended dose of diminazene aceturate,  administered indiscriminately to cattle on day seven of the unfrozen Babesia bovis and Babesia  bigemina bivalent live blood vaccine reaction, was an infection and block treatment method  of immunisation used successfully with no known adverse effect on the parasites or the  development of protective immunity. Continuing with this practice after replacement of the  unfrozen vaccine with deep-frozen monovalent B. bovis and B. bigemina live blood vaccines  resulted in reports of vaccine failure. Laboratory investigation indicated the harmful effect  of block treatment in preventing the development of durable immunity against B. bigemina as opposed to the much lesser effect it had on B. bovis. Consequently the practice was no  longer recommended. A B. bovis vaccination attempt aimed at controlling the disease of dairy  cows in milk (n = 30) resulted in 20% fatalities during the expected vaccine reaction period.  The practice of block treating B. bovis was therefore reinvestigated, this time in a field trial  using dairy cattle in milk (n = 11). Using 0.88 mg/kg (one quarter) of the recommended dose  of diminazene administered on day 12 of the B. bovis vaccine reaction resulted in only two  animals (n = 5) testing ≥ 1/80 positive with the indirect fluorescent antibody test (IFAT)  although parasites could be demonstrated in three. In the untreated control group, by contrast,  five of the vaccinated animals (n = 6) tested ≥ 1/80 positive with IFAT and parasites could  be demonstrated in all. The unsatisfactory outcome obtained in this study, combined with  that of the earlier investigation, indicated that there are more factors that influence successful  vaccination than previously considered. It is therefore concluded that block treatment of the  live frozen South African cattle babesiosis vaccines reactions is not recommended.
authors: Parasites, Vectors and Vector-borne Diseases Programme, ARC-Onderstepoort Veterinary Institute. combrinkm@arc.agric.za.
authors: Michael P
authors: MP
authors: Combrink
authors: Graham
authors: G
authors: Carr
authors: Ben J
authors: BJ
authors: Mans
authors: Frances
authors: F
authors: Marais
mesh_terms: D000818:Animals; D016793:Babesia bovis / Q000276:immunology*; D001404:Babesiosis / Q000517:prevention & control; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology / Q000517:prevention & control*; D004133:Diminazene / Q000031:analogs & derivatives; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect / Q000662:veterinary; D007114:Immunization; D008892:Milk; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D016896:Treatment Outcome; D014611:Vaccination / Q000662:veterinary; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D016052:Protozoan Vaccines; D014613:Vaccines, Attenuated; C003915:diminazene aceturate; D004133:Diminazene