Epidemiology and clinical features of human infection with coxiella burnetii in denmark during 2006-07

S. Bacci*, S. Villumsen, P. Valentiner-Branth, B. Smith, K. A. Krogfelt, K. Mølbak

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

Abstract

Query (Q) fever was virtually unknown in Denmark in 2005, when, after the introduction of new sensitive diagnostic methods for Coxiella burnetii, an increasing number of positive cattle created concern among people with frequent exposure. This led to a dramatic rise in examinations for Q fever among humans in the following 2years. The aim of our study was to assess indication for testing and symptoms in individuals with serological signs of infection with C. burnetii. We performed a case-review study of seropositives among all humans tested for Q fever in 2006-07 in Denmark. Seropositive cases were categorized with acute infection: 4-fold increase in immunoglobulin G (IgG) phase II or concomitant IgM phase II≥1:256 and IgG phase II≥1:1024; and previous infection: IgG phase II≥1:1024. A borderline result was defined as: IgG phase II=1:512. Physicians completed a questionnaire retrospectively. Of the 1613 people tested, 177 (11%) were seropositive [37 (2%) acute infection, 140 (9%) previous infection], 180 had a borderline result. Among 127 seropositives responders, 31% were tested due to symptoms compatible with Q fever after a possible exposure to C. burnetii, 64% were asymptomatic and were tested following relevant exposure only; 64% were males, 43% farmers, 39% veterinarians, 84% had been exposed to cattle. The most frequently reported symptoms were asthenia (25%), myalgia (21%), fever (17%) and headache (13%). About two-thirds of seropositives reported asymptomatic infections, and were tested for Q fever because of concern for occupational exposure to cattle. One-third of the seropositives reported symptoms consistent with Q fever, the majority being mild. Our study provided important evidence that increased requests for Q fever testing in 2006-07 arose from heightened public awareness of the disease, and not from an outbreak of clinical disease. Nonetheless, Q fever should be considered endemic in Denmark.

Original languageEnglish
JournalZoonoses and Public Health
Volume59
Issue number1
Pages (from-to)61-68
Number of pages8
ISSN1863-1959
DOIs
Publication statusPublished - Feb 2012
Externally publishedYes

Keywords

  • Cattle
  • Coxiella burnetii
  • Denmark
  • Epidemiology
  • Q fever
  • Seroprevalence

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