Q Fever in California: IV. Occurrence of Coxiella burnetii in the Placenta of Naturally Infected Sheep

Abstract

Coxiella burnetii. the causative organism of Q fever, was found in the placentas of 21 of 72 sheep (29%). Fifteen, or 35%, of the positive placentas came from serologically positive sheep, and 6 positive placentas (21%) came from serologically negative animals. Negative serological tests in sheep, therefore, should not be interpreted as unequivocally excluding the existence of infection with Coxiella burnetii. The finding of Coxiella burnetii in a relatively high proportion of the placentas of sheep examined points to this organ as an important means of exitus for the rickettsia from the body of the animal, and suggests that this organ constitutes a rich source of infective material for contamination of the environment. The importance of such environmental contamination is discussed.