Chemoprophylactic activity of imidocarb, diminazene and oxytetracycline against Babesia bovis and B. bigemina.
Splenectomized calves treated with imidocarb, diminazene, and oxytetracycline were exposed to Babesia bigemina and B. bovis stabilates at various time intervals following treatment to evaluate prophylactic efficacy. Diminazene showed no residual activity against a B. bigemina challenge given 54 days after treatment. Oxytetracycline appeared responsible for an increased incubation time when given 2 days prior to B. bigemina exposure. Imidocarb showed marked prophylactic efficacy against both B. bigemina and B. bovis. Treatment with 1 or 2 mg kg-1 imidocarb, followed by Babesia exposure on the day of treatment, 7 days after treatment, then every 14 days for 91 days, delayed patent B. bigemina infections for 49 days and patent B. bovis infections for 42 days. Imidocarb at 4 or 5 mg kg-1, followed by similar Babesia exposures, delayed patent B. bovis infections for 68 days, and delayed B. bigemina for 81-103 days, and in some instances prevented infections. The delayed onset of infection due to either B. bigemina or B. bovis, following imidocarb treatment was accompanied by a significantly milder clinical response. Calves not responding to the primary challenge were fully susceptible to stabilate challenge 196 days after treatment. Calves experiencing a mild clinical response to B. bovis following imidocarb treatment and exposure failed to show any signs of response to a 196-day challenge exposure. Calves experiencing a mild clinical response to B. bigemina following imidocarb treatment and exposure did, in some instances, show a second mild response when challenged 196 days after initial treatment.
D000578:Amidines / Q000627:therapeutic use*; D000818:Animals; D001403:Babesia / Q000187:drug effects; D001404:Babesiosis / Q000517:prevention & control*; D002224:Carbanilides / Q000627:therapeutic use*; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D004133:Diminazene / Q000627:therapeutic use*; D007095:Imidocarb / Q000627:therapeutic use*; D008297:Male; D010118:Oxytetracycline / Q000627:therapeutic use*; D013156:Splenectomy / Q000662:veterinary
D000578:Amidines; D002224:Carbanilides; D007095:Imidocarb; D010118:Oxytetracycline; D004133:Diminazene