Q Fever in Como, Northern Italy

To the Editor: Q fever is a widespread zoonosis caused by the intra-cellular gram-negative bacterium Coxiella burnetii. Infection in humans usually occurs through inhalation of contaminated aerosols from parturient fluids of infected animals or contaminated wool (1). C. burnetii also forms spores that may survive for months in the environment in an area where animals have been present, representing a source of infection for persons without any evident contact with animals (2). A self-limited febrile illness, Q fever has the major signs and symptoms of atypical pneumonia and hepatitis. Diagnosis is based on serologic test results. Recently, outbreaks of Q fever have been described in urban areas (3,4), affecting people without any evident risk factor. We describe an outbreak of Q fever in Como, northern Italy, which affected 133 persons. and 1 woman from the prison in Como were admitted to the local hospital with acute pneumonia. At the same time, a 26-year-old man and a 79-year-old woman living in the same area were admitted with the same diagnosis. On admission, all the patients had a high-grade fever and reported a dry cough; 80.0% of patients had a headache, and 70.0% of patients complained of fatigue and weakness. In a few patients, nausea and abdominal pain developed after they were hospitalized. Physical examination of the lungs showed minimal auscultatory abnormalities. Hemoptysis was observed in four patients. Routine blood examinations were performed. In all patients, the leukocyte count was normal, with an increase in the erythrocyte sedimen-tation rate and elevated C-reactive protein levels. The transaminase levels were elevated in eight (47.0%) patients, usually two to three times normal values. Radiographic findings were nonspecific and differed greatly among the patients, who exhibited single and multiple opacities, diffuse interstitial pneumonia, and pleural effusion (in one patient). Bilateral involvement was seen in five (29.4%) patients. All patients received empirical antimicrobial therapy with a β-lactam antimicrobial drug in association with a macrolide or an advanced fluoroquinolone, following the guidelines for community-acquired pneumonia. Patients improved clinically in 48 to 72 hours after antimicrobial drug therapy was started: the fevers resolved and the inflammatory indexes and liver enzyme levels returned to normal. An epidemiologic investigation was started by the Department of Prevention, Azienda Sanitaria Locale, of Como, after it was notified that six patients with acute pneumonia of unknown cause had been admitted to St. Anna Hospital during a 6-day period (January 11–17, 2003); all six patients …