Q fever: a contemporary case series from a Belgian hospital

OBJECTIVES

Q fever is a global zoonosis that can cause both acute and chronic infections in humans through aerogenic transmission. Although Q fever was discovered already 80 years ago, this infectious disease remains largely unknown. We studied a case series in a Belgian tertiary care hospital.

METHODS

A laboratory and file query at our department was performed to detect patients who were newly diagnosed with Q fever from 01 January 2005 to 01 October 2014.

RESULTS

In total, 10 acute Q fever and 5 chronic Q fever infections were identified. An aspecific flu-like illness was the prevailing manifestation of acute Q fever, while this was infective endocarditis in chronic Q fever cases. Noteworthy are the high percentage of myocarditis cases in the acute setting and one case of amyloidosis as a manifestation of chronic Q fever. No evolution from acute to chronic Q fever was noted; overall outcome for both acute and chronic Q fever was favourable with a 94% survival rate.

DISCUSSION

Q fever is an infectious disease characterised by a variable clinical presentation. Detection requires correct assessment of the clinical picture in combination with a laboratory confirmation. Treatment and follow-up are intended to avoid a negative outcome.

Differentiation of Acute Q Fever from Other Infections in Patients Presenting to Hospitals, the Netherlands

Differentiating acute Q fever from infections caused by other pathogens is essential. We conducted a retrospective case-control study to evaluate differences in clinical signs, symptoms, and outcomes for 82 patients with acute Q fever and 52 control patients who had pneumonia, fever and lower respiratory tract symptoms, or fever and hepatitis, but had negative serologic results for Q fever. Patients with acute Q fever were younger and had higher C-reactive protein levels but lower leukocyte counts. However, a large overlap was found. In patients with an indication for prophylaxis, chronic Q fever did not develop after patients received prophylaxis but did develop in 50% of patients who did not receive prophylaxis. Differentiating acute Q fever from other respiratory infections, fever, or hepatitis is not possible without serologic testing or PCR. If risk factors for chronic Q fever are present, prophylactic treatment is advised.

Vaccination against Q fever for biodefense and public health indications

Coxiella burnetii is the etiological agent of Q fever, a disease that is often spread to humans via inhalational exposure to the bacteria from contaminated agricultural sources. Outbreaks have been observed all over the world with larger foci generating interest in vaccination programs, most notably in Australia and the Netherlands. Importantly, exposure rates among military personnel deployed to the Middle East can be relatively high as measured by seroconversion to C. burnetii-specific antibodies. Q fever has been of interest to the biodefense community over the years due to its low infectious dose and environmental stability. Recent advances in cell-free growth and genetics of C. burnetii also make this organism easier to culture and manipulate. While there is a vaccine that is licensed for use in Australia, the combination of biodefense- and public health-related issues associated with Q fever warrant the development of a safer and more effective vaccine against this disease.