With keen interest I read the newsworthy article of Fanoy et al. about the general practitioners’ skill and Q fever hospitalisation risks, recently published in the Netherlands Journal of Medicine.1 The authors emphasized the role of trained primary care health workers in the early diagnosis and proper management of patients with Q fever, to reduce unnecessary hospitalisation.1 This zoonosis mainly occurs through inhalation or ingestion of infected particles, specifically urine, feces, milk, or vaginal mucus from mammals infected with Coxiella burnetii.1-3 Invertebrate hosts like ticks and amoebae may also harbour this agent in human environments.3
Acute infections by C. burnetii may be asymptomatic (20-80%) or manifest themselves by fever, flu-like symptoms, pneumonia or hepatitis. Chronic manifestations are uncommon (1-5%) and include endocarditis, arteritis, pericarditis, osteoarthritis, and lymphadenitis.1-4 Outbreaks in the Netherlands confirmed the potential public health burden of this zoonosis,1,3 the role of small ruminants and the significance of the number of unsuspected chronic infections.3 The Dutch consensus gave rise to new diagnostic criteria for chronic Q fever. Proven cases are defined by positive tests for C. burnetii and endocarditis or vascular infections.3 Worthy of note, vascular involvement of Q fever is more often diagnosed in this region,2,3 where the hospitalisation rate of patients presenting with acute infection is approximately 2-5%.1 The authors highlighted the need for disseminating epidemiological, diagnostic and management updates among general practitioners, to reduce the hospitalisation of patients with Q fever.1 The median duration of hospitalisation was seven days, with a mean diagnostic delay of 29 days; however, prior experience, higher awareness, and more rapid tests can change this situation.1 Fanoy et al.’s original study is indeed a major contribution with respect to public health concerns in high income countries,1 but the following remarks may somehow be appropriate.
The primary course of Q fever is often asymptomatic and misdiagnosis is frequent. For these reasons, early detection of the disease and prevention of long-term complications are challenging tasks. This zoonosis mimics and can be related to endocarditis and large or medium sized arteritis,1-4 so these should be ruled out in cases with clinical suspicion of giant cell or Takayasu’s arteritis.2,4 Q fever is a reportable disease and C. burnetii is classified as a potential bioterrorism agent.3 In areas with a high burden of disease, vaccination of farmers, veterinary and slaughterhouse workers may be useful,3 after screening the antibodies to prevent strong immune reactions. Equipment including N95 respiratory protection is indicated in laboratories and with autopsies.3 Consensual diagnostic and management protocols for Q fever are lacking worldwide.
The author declares no conflict of interest. No funding or financial support was received.