Outbreak of Coxiella burnetii pneumonia

OBJECTIVE: The aim of this study was to describe an outbreak of Q fever pneumonia in the North of Spain. MATERIAL AND METHODS: We report 60 cases of Coxiella burnetii pneumonia in a rural area with 16,000 inhabitants during January and February 2003. The diagnosis was serologically confirmed by indirect immunofluorescence. RESULTS: Mean age of the patients was 46 years and the male/female ratio was 2.5. Overall, 52% of the patients lived in urbanized areas and contact with animals was declared in only 7% of patients. Sixty percent of patients were hospitalized. The most frequent clinical presentation was an acute febrile process (100%) and headache (80%); respiratory symptoms were infrequent. The most common liver function alteration was elevated transaminase levels (35%). Radiologic evidence of a single lobar or segmental alveolar opacity was found in 87% of patients, and most commonly affected the lower lobes. Chest radiographs returned to normal in 70% of patients within the two first months. Empirical treatment consisted of beta-lactams and macrolides in 38%, macrolides alone in 8%, and quinolones in 23%; 27% were treated with beta-lactams alone. No deaths occurred. CONCLUSIONS: Coxiella burnetii infection is very prevalent in the north of Spain and should be suspected and investigated when outbreaks of a pneumonic illness occur.