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

Abstract

The aim of this study is to describe a Q fever outbreak that affected the staff of a machine-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 tested for Q fever serology (immunofluorescence assay with phase II antigen) and detecting Coxiella burnetii DNA using real-time PCR. We interviewed and tested 40 employees (90% of the staff). 33 employees, all of them men, had positive serology (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 negative men, 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%) had developed radiologically confirmed pneumonia. We obtained 28 blood samples, 22 faeces samples, 11 milk samples, and one vaginal swab from 28 goats resting in a stable near the factory. Serology was positive in 18 goats (64.3%). All environmental samples were negative.