Targeted Screening for Chronic Q Fever, the Netherlands

Abstract

Early detection of and treatment for chronic Q fever might prevent potentially life-threatening complications. We performed a chronic Q fever screening program in general practitioner practices in the Netherlands 10 years after a large Q fever outbreak. Thirteen general practitioner practices located in outbreak areas selected 3,419 patients who had specific underlying medical conditions, of whom 1,642 (48%) participated. Immunofluorescence assay of serum showed that 289 (18%) of 1,642 participants had a previous Coxiella burnetii infection (IgG II titer >1:64), and 9 patients were suspected of having chronic Q fever (IgG I y titer >1:512). After medical evaluation, 4 of those patients received a chronic Q fever diagnosis. The cost of screening was higher than estimated earlier, but the program was still cost-effective in certain high risk groups. Years after a large Q fever outbreak, targeted screening still detected patients with chronic Q fever and is estimated to be cost-effective.

Keywords: Coxiella burnetii; Q fever; aneurysm; bacteria; chronic Q fever; cost effectiveness; general practitioner; heart valve disease; immunocompromised patient; screening program; targeted screening; the Netherlands; vascular disease.

Figure 1

Locations of participating general practices (numbers in circles) in the Netherlands and seroprevalence rates for chronic Q fever measured in study of targeted screening program to detect chronic Q fever. Colors indicate areas with high incidence of acute Q fever patients or areas near an infected farm that had abortion waves during the outbreak of 2007–2010.

Figure 2

Relationship between the prevalence of chronic Q fever and incremental cost-effectiveness ratio of a screening program to detect chronic Q fever, the Netherlands, and screening costs for the program compared with a previously published analysis (7). Symbols on the line are based on a high-prevalence and low prevalence rate scenario as used in the previously published analysis and are based on actual prevalence rates found in this study. CVRF, cardiovascular risk factor; IC, immunocompromised; ICER, incremental cost-effectiveness ratio; QALY, quality-adjusted life year.