Seroprevalence of Q Fever in the United States, 2003–2004

We performed serum testing for IgG antibodies against Coxiella burnetii (phase I and phase II) and analyzed questionnaire data from 4,437 adults ≥ 20 years of age who participated in the National Health and Nutrition Examination Survey 2003–2004 survey cycle. National Q fever seroprevalence was determined by enzyme-linked immunosorbent assay and confirmed by using immunofluorescent antibody testing. Overall seroprevalence for Coxiella burnetii...