Figure 5: Survival, histomorphometry and pulmonary bacillary loads after intratracheal challenge with M. bovis: (A) Strains AN5 and 302 (hypervirulent strains) and 534 (low virulence) were used to challenge BALB/c mice vaccinated with mce2A mutant, BCG or non-vaccinated control animals and their survival was recorded during four months (20 mice per strain). (B) Percentage of lung surface affected by pneumonia determined by automated morphometry. (C) Lung bacillary loads, both determinations were done after 60 days of challenge. Asterisks represent statistical significance (P < 0.05).