Evaluation of BCG vaccine and Mycobacterium bovis culture filtrate proteins against bovine tuberculosis.

The objective of this study was to evaluate the degree of protection against TB of three immunogens in calves experimentally challenged with a pathogenic Mycobacterium bovis strain by identification of lesions during necropsy. Twenty-four calves free of TB were distributed into four groups: group 1 was inoculated with M. bovis CFPE, group 2 with CFPE/IFN-gamma, group 3 with M. bovis BCG, and group 4 remained as control. After 6 months all animals were challenged with an M. bovis field strain, and 6 months later the animals were euthanized and the presence of lesions was evaluated. Several degrees of protection were observed in the vaccinated groups, particularly in the group vaccinated with BCG, as shown by the absence or decrease in severity of lesions. Vaccination could be useful in high-prevalence zones where it is economically unfeasible to slaughter animals.