[Study of the reactivity and immunogenicity of a combined vaccine against abortion due to coxiellosis and chlamydiosis in sheep].

Reactogenicity was studied in a combined vaccine against Q-fever and chlamydia-induced abortion in ewes; the vaccine consisted of a mixture of purified corpuscles of Chlamydia psittaci (100 micrograms) and Coxiella burnetii (50 micrograms). The immunogenicity of the combined vaccine, evaluated by the number of positive serums after vaccination and by the average geometric titre of antibodies, was the same as that of the vaccine separate constituents as to the antibodies to C. burnetii, but somewhat higher in the case of antibodies to Chlamydia psittaci. When studied on a smaller number of ewes, the combined vaccine had an optimum immunogenicity in the cases of the prevalence of Chlamydia psittaci over C. burnetii in the vaccine.