The use of the Brucella abortus strain 19 in the medical prophylaxis of bovine brucellosis in northern Cameroon: study of the effect of the vaccinal dose on seroconversion rate and duration in zebu females

Abstract

Four herds of zebus from northern Cameroon totalling 136 animals were vaccinated subcutaneously with the following doses of Brucella abortus strain 19: 5x10  puissance 9 colony-forming units (CFU), 10 puissance 9 UFC, 5 x 10 puissance 8 UFC et 10 puissance 7 UFC. Twenty-eight days after vaccination, the following seroconversion rates were observed respectively: 97.4, 96.2, 84.2 and 73.3 %. Of the 52 animals which could be tested subsequently including 39 over one year old on the vaccination day, only one showed antibodies 6 months after vaccination. The cost price of the strain 19 vaccine produced at the Boklé National Veterinary Laboratory was estimated to be 65 F CFA at the 10 puissance 9  CFU dose and 1,740 F CFA at the 5x10 puissance 10 CFU dose usually recommended. The use of the Buck 19 strain in the medical prophylaxis of bovine brucellosis in northern Cameroon is discussed.