Experimental infection of Coxiella burnetii in chicken: clinical symptoms, serologic response, and transmission through egg.

Young laying hens were infected with Coxiella burnetii to study egg transmission, clinical and serologic responses, excretion of the agent in feces, and its persistence in internal organs. No clinical symptoms were noticed. The birds developed good titers in a capillary agglutination test by 13 days postinfection (DPI), which peaked at 30 DPI and therafter declined gradually, becoming negative in some birds around 90 DPI. In vivo and in vitro egg transmission of the agent could not be demonstrated. C. burnetii was recovered at 90 DPI from spleen and liver but not from kidney and ovary.