Population Screening for Chronic Q-Fever Seven Years after a Major Outbreak

<div><p>Introduction</p><p>From 2007 through 2010, the Netherlands experienced a large Q-fever epidemic, with 4,107 notifications. The most serious complication of Q-fever is chronic Q-fever.</p><p>Method</p><p>In 2014, we contacted all 2,161 adult inhabitants of the first village in the Netherlands affected by the Q-fever epidemic and offered to test for antibodies against <i>Coxiella burnetii</i> using immunofluorescence assay (IFA) to screen for chronic infections and assess whether large-scale population screening elsewhere is warranted.</p><p>Results</p><p>Of the 1,517 participants, 33.8% were IFA-positive. Six IFA-positive participants had an IgG phase I titer ≥1:512. Two of these six participants were previously diagnosed with chronic Q-fever. Chronic infection was diagnosed in one of the other four participants after clinical examination.</p><p>Conclusions</p><p>Seven years after the initial outbreak, seroprevalence remains high, but the yield of screening the general population for chronic Q-fever is low. A policy of screening known high-risk groups for chronic Q-fever in outbreak areas directly following an outbreak might be more efficient than population screening. A cost-effectiveness analysis should also be performed before initiating a population screening program for chronic Q-fever.</p></div>