Combined vaccination of live 1B Chlamydophila abortus and killed phase I Coxiella burnetii vaccine does not destroy protection against chlamydiosis in a mouse model

Abstract

Q fever and chlamydiosis often affect ovine and caprine flocks simultaneously or successively. Combination vaccines effective against these 2 diseases would be of great value in veterinary medicine. Unfortunately, the current effective vaccines are a live vaccine for chlamydiosis and killed vaccine for Q fever. Vaccination of mice with live chlamydiosis vaccine 1B and killed phase I vaccine against Q fever at 2 points on the back at the same time produced good protection against chlamydial abortion. This suggests that it may be possible to vaccinate ewes and goats against chlamydiosis and Q fever simultaneously.

Figure 1

Effectiveness against virulent C. abortus strain AB7 challenge,for live chlamydiosis vaccine strain 1B alone (group 1B/AB7) combined with phase I Q fever vaccine Q VAX (FQ) (CEVA) (group 1B-FQ/AB7) in a mouse model. Two groups of 20 vaccinated and 1 group of 20 unvaccinated pregnant mice (group AB7) were challenged with 1 × 10⁵ plaque-forming units (PFU) of C. abortus strain (AB7), and the average number of living offspring per mouse was recorded daily for 8 d. The number was not significantly different between the unchallenged control group (pregnancy group) and the vaccinated groups, but was significantly different between the 3 groups and the unvaccinated challenged group (P < 0.0001).