Author: Vanessa Mora
Editor: Leah Farquharson
Query Fever (Q Fever) is an acute and chronic zoonotic disease caused by Coxiella burnetti (Dupont & Raoult, 2008). Coxiella burnetti is a bacterial pathogen mainly present in domestic cattle, sheep, and goats; however, it can also be present in dogs, cats, pigs, camels, wild birds, and rodents (Maurin & Raoult, 1999). Ingestion and inhalation of Coxiella burnetti results in bacteria in the bloodstream, where life-threatening manifestations may occur (Patil & Regunath, 2020).
Humans are exposed to Q Fever when animals excrete Coxiella burnetii in their urine, feces, wool, milk, and parturient fluids (Dupont & Raoult, 2008). These contaminated products, mainly the parturient fluids containing high concentrations of Coxiella burnetii can become aerosolized, and infect humans via inhalation (Gürtler et al., 2014). The ingestion of raw milk products may also infect humans (Gürtler et al., 2014). Transmission from person to person is possible through contact with parturient women but occurs rarely (Porter et al., 2011).
Q fever presents worldwide, except in New Zealand since New Zealand may be free from Coxiella burnetii and consequently Q fever (Maurin & Raoult,1999). Higher indices of Q Fever are reported in the Netherlands, France, and Australia with approximately 500 cases per million (Hartzell et al., 2008). In these regions, patients with Q Fever were usually living in rural areas or in a 5km radius of infected livestock, having contact with placenta from sheep, and consuming contaminated milk products (Frankel et al., 2011).
Query fever arises from a coccobacillus pathogen called Coxiella burnetii. The infectious phase (Phase I) of Coxiella burnetii is resistant to extreme heat, high or low pH, desiccation, chemical products, disinfectants, UV Rays, and osmotic pressure. These features allow the bacteria to survive in the environment and in the host for long periods of time (Porter et al., 2011).
Acute Query Fever
Half of the patients are asymptomatic. Following an incubation period of 3-30 days, symptoms in symptomatic patients may include the following:
- Fever and chills
- Chest pain and Cough
- Nausea and Vomiting
- Diarrhea ( Maurin & Raoult, 1999)
Chronic Query Fever
The most common symptoms of Chronic Query Fever include the following:
- Interstitial lung fibrosis
- Recurring fever (Gürtler et al., 2014)
Risk factors that increase the likelihood of acquiring Q Fever include occupations that require contact with domestic animals and dairy products, such as farmers, veterinarians, abattoir workers, and laboratory personnel (Maurin & Raoult,1999). The absence of a mask and protective clothing in such workplaces also increases the risk of acquiring Q fever (Porter et al., 2011).
Other risk factors include sex: males are more likely to become infected with Query Fever, age: individuals over the age of 15 are at an increased risk of Q Fever, pregnancy, previous cardiac valve defects, HIV, cancer, lymphoma, and having an impaired immune system (Maurin & Raoult,1999).
A thorough physical examination will be performed and the patient’s history will be obtained by noting the patient’s exposure history including, contact with domestic animals, consumption of raw milk products, any recent travel to rural areas with greater risk of Q fever, and their current symptoms (Maurin & Raoult, 1999). If the patient notes any of the symptoms listed above the physician will perform further tests and diagnosis (Maurin & Raoult, 1999).
Diagnostic tests performed to detect Coxiella burnetii antibodies include enzyme-linked immunosorbent assay (ELISA), agglutination test, complement-fixation assay (CFA), and micro-immunofluorescence assay (Gürtler et al., 2014). Coxiella burnetii antibodies are detectable 2-3 weeks following the presentation of clinical symptoms (Gürtler et al., 2014).
A nucleic acid amplification test (PCR) is may also be performed to confirm the presence of Coxiella burnetii DNA in the patient’s blood, 2 weeks after transmission (Gürtler et al., 2014). A chest x-ray may be performed if clinical symptoms suggest pneumonia (Patil & Regunath, 2020). An echocardiogram is performed to note if the patient has endocarditis (Patil & Regunath, 2020).
Adult patients with Acute Q fever are treated with doxycycline (Kersh, 2013).
Co-trimoxazole is recommended for pregnant women and children under the age of 8 (Kersh, 2013). Other antibiotics that have been successful in treating Acute Q fever are Rifampin and Quinolones (Kersh, 2013). If the patient is diagnosed with Chronic Q fever, doxycycline combined with hydroxychloroquine will be prescribed for at least 18 months (Kersh, 2013).
Patients with Q fever endocarditis may require valve replacement surgery in addition to antibiotic treatment (Maurin & Raoult, 1999).
Articles on Misdiagnosis
Kampschreur, L.M. (2015). Chronic Q Fever Diagnosis—Consensus Guideline versus Expert Opinion. Emerging Infectious Diseases, 21(7), 1183-1188. DOI: 10.3201/eid2107.130955.
Million, M., & D. Raoult. (2017). No such thing as chronic Q fever. Emerging Infectious Diseases, 23(5): 856–857. DOI:: 10.3201/eid2305.151159.
Nett, R.J., Book, E., & A.D. Anderson. (2012). Q fever with unusual exposure history: a classic presentation of a commonly misdiagnosed disease. Case Reports in Infectious Diseases. DOI: 10.1155/2012/916142
Frankel, D., Richet, H., Renvoisé, A., & Raoult, D. (2011). Q fever in France, 1985-2009. Emerging infectious diseases, 17(3), 350–356.
Gürtler, L., Bauerfeind, U., Blümel, J., Burger, R., Drosten, C., Gröner, A., Heiden, M., Hildebrandt, M., Jansen, B., Offergeld, R., Pauli, G., Seitz, R., Schlenkrich, U., Schottstedt, V., Strobel, J., & Willkommen, H. (2014). Coxiella burnetii – Pathogenic Agent of Q (Query) Fever. Transfusion medicine and hemotherapy : offizielles Organ der Deutschen Gesellschaft für Transfusionsmedizin und Immunhämatologie, 41(1), 60–72.
Kersh G. J. (2013). Antimicrobial therapies for Q fever. Expert review of anti-infective therapy, 11(11), 1207–1214.
Maurin, M., & Raoult, D. (1999). Q fever. Clinical microbiology reviews, 12(4), 518–553.
Porter, S. R., Czaplicki, G., Mainil, J., Guattéo, R., & Saegerman, C. (2011). Q Fever: current state of knowledge and perspectives of research of a neglected zoonosis. International journal of microbiology, 2011, 248418.
Tissot-Dupont, H., & Raoult, D. (2008). Q Fever. Infectious Disease Clinics of North America, 22(3), 505-514.