Evidence of reproductive failure and lack of perinatal transmission of Bartonella henselae in experimentally infected cats

Five female specific pathogen-free (SPF) cats inoculated intradermally with B. henselae and bacteremic for 4 weeks, and one cat inoculated with 0.9% NaCl, were bred with uninfected SPF male cats. The uninfected female became pregnant with one breeding, while three infected cats became pregnant 1–12 weeks later, after repeated breedings. Two infected females either did not become pregnant or maintain pregnancies despite repeated breedings. Infected cats produced anti-B. henselae IgM and IgG antibodies. Fetuses and kittens of infected cats were not infected and did not produce anti-B. henselae antibodies. Male cats bred with infected females did not become infected or seroconvert. Maternal anti-B. henselae IgG antibodies detected in sera of kittens 2 weeks post-partum were no longer detectable 10 weeks post-partum. These findings suggest that B. henselae causes reproductive failure in female cats, but is not transmitted transplacentally, in colostrum or milk, or venereally. Infected cats immunosuppressed with methylprednisolone acetate after their kittens were weaned had no detectable bacteria in tissues, suggesting that they were no longer infected.