Study and Management of a Q Fever Outbreak among Machine Tool Workers in the Basque Country (Spain)

The aim of this study is to describe a Q fever outbreak that affected the staff of amachine-tool factory in the Basque Country between 2009/12/20 and 2010/02/23.Study subjects were interviewed using a Q fever specific questionnaire and testedfor Q fever serology (immunofluorescence assay with phase II antigen) anddetecting Coxiella burnetii DNA using real-time PCR. We interviewed and tested 40employees (90% of the staff). 33 employees, all of them men, had positiveserology (attack rate 82.5%, 95% CI: 70.2–94.8). Mean age was 43.7 years(95% CI: 38.7–48.7) in positive men, 33.7 years (95% CI: −16.6–83.9) in negativemen, and 36.25 (95% CI: 27.5–45.0) in women (all negatives). 15 cases (45.5%)were asymptomatic, 9 (27.3%) had flu-like symptoms, and the other 9 (27.3%) haddeveloped radiologically confirmed pneumonia. We obtained 28 blood samples, 22faeces samples, 11 milk samples, and one vaginal swab from 28 goats resting in astable near the factory. Serology was positive in 18 goats (64.3%). Allenvironmental samples were negative