title: Chronic Q fever: An ongoing challenge in diagnosis and management.
abstract: Chronic Q fever is a potentially fatal disease. The current difficulty in the diagnosis of this condition is discussed in the present article. A 51-year-old woman with a history of aortic valve replacement presented with complaints of feeling generally unwell, pyrexia and occasional unproductive cough over a period of several weeks. Phase 1 immunoglobulin G titre to Coxiella burnetii was initially detected at a low level (1:320, detected using immunofluorescence) and was not considered to be significant according to the modified Duke criteria. Later in the course of her illness, the patient's antibody titre rose to a high level (1:1280). The issues regarding current laboratory diagnosis and management of Q fever are discussed. Chronic Q fever can be associated with an inadequate serological response. Close follow-up of cases is essential. The recommended serological criteria for the diagnosis of Q fever endocarditis needs to be revisited.
authors.affiliation: Department of Clinical Microbiology & Infection Control, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
authors.forename: Ira
authors.initials: I
authors.lastname: Das
authors.affiliation: Department of Clinical Microbiology & Infection Control, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
authors.forename: Nicola
authors.initials: N
authors.lastname: Guest
authors.affiliation: Department of Cardiology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
authors.forename: Richard
authors.initials: R
authors.lastname: Steeds
authors.affiliation: Department of Nephrology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Hewins
keywords: Echocardiogram; Endocarditis; Modified Duke criteria; Q fever serology