Evaluation of a diagnostic algorithm for acute Q fever in an outbreak setting

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Epidemiology

Background:

• The 2009 Q fever outbreak in the Netherlands necessitated efficient diagnostic strategies.
• Traditional diagnostic methods for Q fever can be resource-intensive.

Purpose of the Study:

• To evaluate a novel diagnostic algorithm for acute Q fever.
• To assess the impact of an enzyme-linked immunosorbent assay (MII screen) on diagnostic workflow.
• To determine the contribution of polymerase chain reaction (PCR) to Q fever diagnosis.

Main Methods:

• Retrospective evaluation of 825 patients during a 17-day period.
• Implementation of a diagnostic algorithm starting with an MII screen for Coxiella burnetii antibodies.
• Subsequent use of immunofluorescence assay or PCR based on MII screen results and clinical data.

Main Results:

• Acute Q fever was diagnosed in 256 patients.
• The MII screen reduced the number of immunofluorescence assays by over 80%.
• PCR analysis contributed to the diagnosis in 103 patients.
• Diagnostic challenges included missing onset dates and lack of follow-up samples.

Conclusions:

• The MII screen is an effective initial step for diagnosing acute Q fever, significantly reducing workload.
• PCR plays a valuable role in confirming Q fever diagnoses.
• Improved data collection, such as date of onset and follow-up samples, is crucial for effective diagnostics.