[Lacteal and placental excretion of Coxiella burnetti, agent of Q fever, in the cow. Importance and prevention].

Q Fever, a true zoonosis, comes always from an animal contamination. The causes of human infection are mainly the pulmonary route and at a less degree the oral route. We describe, from a mouse model, a method of quantitative evaluation of the excretion of Coxiella in the milk. Our experiments done on 400 samples of milk of clinically infected cows, show that the mammal excretion is low and irregular. Moreover it needs 10,000 times more of Coxiella to the mouse by oral route than by the intraperitoneal route. These facts seem to minimize the importance of the digestive route in the human infection. The most important cause remains the inhalation of infected dusts. The prevention of this animal excretion goes through classical steps of sanitary prophylaxis. Moreover vaccination, antibiotherapy, or association of both reduce but do not stop the excretion in the environment. The application of all or of a part of these measures will strongly reduce the human contamination.