Table 3.

Protective efficacy of vaccine candidates against a B. ovis PA experimental challenge in rams.

Vaccine (CFU dose)	No. infected animals/total (%)a	No. infected organs/total (%)b	No. severely infected animals (%)a,c/no. severely infected organs (%)b
Bov::CAΔwadB (1 × 1010)	11/14 (78.6)	41/112 (36.6)	4 (28.6)d/11 (9.8)d
Rev1::wbdRΔwbkC (2.5 × 1010)	7/14 (50.0)	30/112 (26.8)d	5 (35.7)/13 (11.6)d
H38ΔwbkF (2.5 × 1010)	2/14 (16.7)e,f	6/112 (5.4)e,f	1 (7.1)e,f/2 (1.8)e,f
Rev 1 (2 × 109)	3/14 (21.4)d	12/112 (10.7)e	1 (7.1)e/1 (0.9)e
Unvaccinated	11/13 (84.6)	64/104 (61.5)	9 (69.2)/30 (28.8)

^aStatistical comparisons by Chi-square test (with Fisher-Yates correction when required). ^bStatistical comparisons by STEPBOOT MULTTEST (SAS); ^cseverely infected animals were those showing at least one organ sample with an infection level ≥ 3 (≥ 26 CFU/plate). ^dSignificant difference (P < 0.05) versus unvaccinated control; ^eHigh significant difference (P < 0.001) vs. unvaccinated control; ^fno significant (P > 0.05) versus Rev 1 vaccinated group.