An infection caused by the microorganism
Coxiella burnetii (rickettsia), a parasite of cattle. Cattle excrete the microorganisms in their milk or feces. Humans
become infected usually by
inhaling dust that is
contaminated by infected animal material; sometimes infection comes from drinking infected milk,
since the rickettsiae are
somewhat resistant to pasteurization.
After an incubation
period of two to four weeks, symptoms appear suddenly. These consist of fever, headaches, prostration, cough, and muscle and chest pain. X-ray studies usually show an inflammation of the lung, although the
cough may be slight.
Occasionally the heart may be affected, sometimes months
after the original infection. In severe cases, hepatitis is common. The disease may be acute, or
chronic and relapsing, but is rarely fatal.
Prevention is by avoiding
contact with infected cattle. If the disease develops,
symptoms may be suppressed by the administration of antibiotics, although this will not necessarily eradicate the infection.