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Q Fever

A bacterial infection caused by Coxiella burnetii. It is transmitted to humans by the inhalation of infected air particles or contact with fluids and feces of infected animals.

PubMed Health Glossary
(Source: NIH - National Cancer Institute)

About Q Fever

Q fever can cause acute or chronic illness in humans, who usually acquire infection after contact with infected animals or exposure to contaminated environments.

The acute symptoms caused by infection with Coxiella burnetii usually develop within 2-3 weeks of exposure, although as many as half of humans infected with C. burnetii do not show symptoms.

The following is a list of symptoms commonly seen with acute Q fever. However, it is important to note that the combination of symptoms varies greatly from person to person.

  • high fevers (up to 104-105°F)
  • severe headache
  • general malaise
  • myalgia
  • chills and/or sweats
  • non-productive cough
  • nausea
  • vomiting
  • diarrhea
  • abdominal pain
  • chest pain

Although most persons with acute Q fever infection recover, others may experience serious illness with complications that may include pneumonia, granulomatous hepatitis (inflammation of the liver), myocarditis (inflammation of the heart tissue) and central nervous system complications. Pregnant women who are infected may be at risk for pre-term delivery or miscarriage. The estimated case fatality rate (i.e. the proportion of persons who die as a result of their infection) is low, at less than 2% of hospitalized patients. Treatment with the correct antibiotic may shorten the course of illness for acute Q fever...Read more about Q Fever
CDC - Centers for Disease Control and Prevention

What works? Research summarized

Evidence reviews

A review of the efficacy of human Q fever vaccine registered in Australia

This review assessed the efficacy of the human Q fever vaccine registered in Australia. The authors concluded that, despite study limitations, the vaccine had considerable protective benefit in high-risk environments. Poor reporting, lack of formal validity assessment and the non-randomised nature of much evidence meant that, although the conclusions reflected the results of the review, their reliability was unclear.

The effectiveness of Coxiella burnetii vaccines in occupationally exposed populations: a systematic review and meta-analysis

To estimate the effect of vaccination in preventing acute Q fever in individuals occupationally exposed to Coxiella burnetii, a systematic review and meta-analysis were undertaken in controlled trials and observational studies. Publications were obtained through a scoping study of English and non-English articles, and those reporting a commercially licensed or licensable vaccine compared with an unvaccinated or placebo control group were included in the review. Two authors performed independent assessment of risk of systematic error and data extraction. One controlled trial and five cohort publications met the inclusion criteria. All trials used a Henzerling phase I vaccine. A random-effects meta-analysis estimated significant protection in abattoir workers (RR = 0.07; 95% confidence interval [CI] 0.02-0.22) compared with the control individuals. In individuals with rare or sporadic contact with the abattoir, a significant benefit of vaccination was also found (RR = 0.06; 95% CI 0-0.93). Overall, the vaccine effectively prevented acute Q fever in individuals responsible for handling animals or their products and those working in the abattoir but not directly exposed to animals (RR = 0.06; 95% CI 0.02-0.18). Caution must be taken when interpreting the effect of C. burnetii vaccination as significant heterogeneity amongst publications was observed. A meta-regression found no significant univariate associations. This may reflect the uncertainty provided by reported data in the cohort publications. Potential systematic biases were present in the publications, and evidence included may not be sufficiently robust to extrapolate the effect of vaccination on occupationally exposed groups beyond the population of abattoir employees in Australia where all included studies occurred.

Preventive occupational health interventions in the meat processing industry in upper-middle and high-income countries: a systematic review on their effectiveness

OBJECTIVE: To investigate the effectiveness of occupational health interventions in the meat processing industry on work and health-related outcomes.

Terms to know

A large group of single-cell microorganisms. Some cause infections and disease in animals and humans. The singular of bacteria is bacterium.
Coxiella Burnetii
The causative agent of Q fever. A small Gram-negative bacterium.
Gram-negative Bacteria
Bacteria that show up as pink (negative) when treated by the gram-staining method.
Myalgia (Muscle Ache)
Pain in a muscle or group of muscles.

More about Q Fever

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Other terms to know: See all 4
Bacteria, Coxiella Burnetii, Gram-negative Bacteria

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