REV1 and infection: Regarding male mice, it was shown that there was a statistically significant decrease (p < 0.01) in splenic colonization in mice inoculated with B. melitensis LVM31 mutant strain at 4, 8, and 12 weeks post infection compared to B. melitensis Bm133 virulent strain and with B. melitensis Rev1 vaccine strain (Fig. 1B).