Repeated pregnancies in BALB/c mice infected with Coxiella burnetii cause disseminated infection, resulting in stillbirth and endocarditis

Q fever is a widespread zoonosis caused by the obligate intracellular bacte rium Coxiella burnetii. Although this highly virulent organism is most conc entrated in mammals during parturition, there are few reports on the manife stations of perinatal Q fever in the human and animal host. The affinity of C, burnetii to pregnancy and its abortifacient potential were investigated in a murine animal model. Intraperitoneal infection of female BALB/c mice with C. burnetii, followed by repeated pregnancies over a 2-year period, re sulted in persistent infection associated with abortion and perinatal death , with a statistically significant decrease in viable offspring. In additio n, endocarditis occurred in 2 of the adult animals, and C. burnetii antigen and DNA were detected in their heart valves. Taken together, these results demonstrate the abortifacient potential of C. burnetii and the increased r isk of persistent infection and endocarditis in pregnant mice, probably rel ated to a decline in cellular immunity during pregnancy.