Q fever. A common treatable cause of endemic nonbacterial pneumonia

In an area known for endemic Q fever, eight of 52 cases of nonbacterial pneumonia were proven to be caused by infection with Coxiella burnettii . Intimate contact with a possible source of infection was excluded in all patients and dust-borne transmission of the rickettsial organism from animal to man was implicated. Symptoms, physical findings, and laboratory and roentgenographic data were similar to those previously described in Q fever and were indistinguishable from those found in viral or mycoplasmal pneumonia. All patients treated with tetracycline showed a dramatic response within 24 hours. Q fever must be considered in the diagnosis whenever nonbacterial pneumonia occurs in late summer or early fall in an area where Q fever is endemic. Early diagnosis and treatment will significantly reduce morbidity.