In September 2004, we searched for articles published in English from 1999 using MEDLINE, Biological Abstracts, Embase, PsycINFO, and CINAHL. A search with the terms “Coxiella”, “burnetii”, “burneti”, “coxiellosis”, “coxiell*”, and “Q fever” identified 309 journal articles. We also read older papers cited in these, or already known to the authors, and some papers published after September, 2004.
SeminarQ fever
Introduction
Edward Derrick named the illness he described in 1937 as Q [for query] fever,1 “until fuller knowledge should allow a better name”.2 Within 10 years, the bacterium was described, reservoirs found, and the route of infection elucidated;1 but the name has persisted—perhaps because researchers like using it in their article titles.3, 4 This review is primarily written for generalists, particularly those responsible for rural communities.
Derrick's description of nine Q fever cases from Queensland2 is the fourth most cited article from the Medical Journal of Australia.5 The name Coxiella burnetii reflects the almost simultaneous isolation of the organism by American and Australian researchers. Cox identified bacteria from ticks collected near Nine Mile Creek in Montana,6 while Burnet's isolates came from Derrick's patients.7, 8
Section snippets
Microbiology
C burnetii was originally named Rickettsia burneti since it shares some characteristics with the Rickettsiae, such as being an obligate intracellular organism and having a tick reservoir. However, sequencing of the C burnetii 16S rRNA9 and genome10 has identified substantial homology with Legionella pneumophila.11 Both these bacteria are in the gamma subdivision of the proteobacteria, distantly placed from Rickettsiae which belong in the alpha subdivision.12 Although the adjective “rickettsial”
Disease manifestation
Q fever can be acute or chronic, and long-term sequelae are gaining acceptance as a third category of the disease. Asymptomatic infection is common. In an outbreak in a Swiss valley, about 50% of people who seroconverted became ill.25
Diagnosis
Signs and symptoms are non-specific so of little help in diagnosis. A history of exposure to cattle, sheep or goats is useful, but contact may be indirect and unrecognised.12, 26, 46, 66
The clinician suspecting Q fever must check for heart valve disease and immunosuppression, because these conditions predispose to the development of endocarditis.39
Acute disease
Doxycycline, 100 mg twice daily for 14 days75 is recommended for acute illness. Antibiotic treatment lessens the time in which the patient has fever,42 and hastens recovery from pneumonia.34 In a randomised controlled trial76 and in retrospective studies, doxycycline outperforms other antibiotics including erythromycin.42, 44 Newer macrolides and fluoroquinolones show promise.42, 75, 77 Starting antibiotic therapy after the third day of fever might not change outcomes,9 although in the
Bioterrorism
The incubation period is usually 2–3 weeks,75 but is dose-dependent2, 81 with 4 days82 and 6 weeks representing the extremes.12, 61 Claims that a single C burnetii organism can cause disease in a susceptible person13, 61, 83, 84 have contributed to C burnetii being classified as a category B bioterrorism agent. Although it has a low case fatality rate, it meets criteria such as ease of manufacture, stability in the environment, and ability to cause disease.61 Q fever is also part of military
Vaccination
The first case of Q fever identified in the USA was laboratory acquired,8 so vaccines for laboratory staff were soon produced. These were effective, but large local reactions occurred, including sterile abscesses with draining sinuses. The reactions occurred in those with pre-existing immunity, including those previously vaccinated.23
Live,129 whole-cell, and acellular Q-fever vaccines have been developed. A whole-cell vaccine is licensed in Australia (Q-Vax).29 Acellular vaccines include a
Future directions
The last decade has seen major improvements in serological diagnosis and the treatment of chronic disease. Serious long-term sequelae have been suggested, and the genome has been mapped.
Q-fever immunology remains a challenge. How does the bacterium thrive in the phagolysosome? Are long-term sequelae caused by persistence of the live organism or by persistence of specific antigens?
What is the incidence of disease, by region, occupation, and age group? Is there significant regional variation in
Search strategy and selection criteria
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Turning a tiger into a house cat: using Legionella pneumophila to study Coxiella burnetii
Trends Microbiol
(2004)- et al.
Coxiella burnetii seropositivity in parturient women is associated with adverse pregnancy outcomes
Am J Obstet Gynecol
(2003) - et al.
Q fever in children
Lancet Infect Dis
(2002) - et al.
Developmental biology of Coxiella burnetii
Trends Microbiol
(1999) - et al.
An economic evaluation of increased uptake in Q fever vaccination among meat and agricultural industry workers following implementation of the National Q Fever Management Program
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Q fever—a review and issues for the next century
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Q fever in an urban area
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Q-fever presenting with intractable diarrhea and fever with both responding to indomethacin
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Q fever (coxiellosis): epidemiology and pathogenesis
Res Vet Sci
The detection of Coxiella burnetii from ovine genital swabs, milk and fecal samples by the use of a single touchdown polymerase chain reaction
Vet Microbiol
Brucellosis and Q-fever seroprevalences of nomadic pastoralists and their livestock in Chad
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The Query Fever—the Elkington Oration
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Q fever, a new fever entity: clinical features, diagnosis and laboratory investigation
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Q fever: still a query after all these years
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Q fever: Still a query and underestimated infectious disease
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Jewels in the crown: The Medical Journal of Australia's 10 most-cited articles
Med J Aust
A filter-passing infectious agent isolated from ticks
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Clin Microbiol Rev
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Q Fever
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Long term vascular complications of Coxiella burnetii infection in Switzerland: cohort study
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Diagnosis of Q Fever
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Molecular pathogenesis of Coxiella burnetii in a genomics era
Ann N Y Acad Sci
Infectivity, virulence, and pathogenicity of Coxiella burnetii for various hosts
Coxiella burnetii exhibits morphological change and delays phagolysosomal fusion after internalization by J774A.1 cells
Infect Immun
Chromosomal DNA deletions explain phenotypic characteristics of two antigenic variants, phase II and RSA 514 (Crazy), of the Coxiella burnetii Nine Mile strain
Infect Immun
Prevention of Coxiella burnetii infection: vaccines and guidelines for those at risk
Molecular characterization of Coxiella burnetii isolates
Epidemiol Infect
An important outbreak of human Q fever in a Swiss Alpine valley
Int J Epidemiol
Q fever in humans and animals in the United States
Vector Borne Zoonotic Dis
Coxiella burnetii pericarditis: Report of 15 cases and review
Clin Infect Dis
Epidemiologic features and clinical presentation of acute Q fever in hospitalized patients: 323 French cases
Am J Med
Myocarditis, a rare but severe manifestation of Q fever: report of 8 cases and review of the literature
Clin Infect Dis
Q fever: epidemiology, clinical features and prognosis. A study from 1983 to 1999 in the South of Spain
J Infect
The course of infection with Coxiella burnetii
Med J Aust
Investigation of a slaughterhouse-related outbreak of Q fever in the French Alps
Eur J Clin Microbiol Infect Dis
Coxiella burnetii pneumonia
Eur Respir J
Q fever, a study of 111 consecutive cases
Med J Aust
Cardiac valves in patients with Q fever endocarditis: microbiological, molecular, histologic studies
J Infect Dis
Correlation between serum doxycycline concentrations and serologic evolution in patients with Coxiella burnetii endocarditis
J Infect Dis
Risk factors and prevention of Q fever endocarditis
Clin Infect Dis
Consecutive epidemics of Q fever in a residential facility for drug abusers: impact on persons with human immunodeficiency virus infection
Clin Infect Dis
Q fever endocarditis in Queensland
Circulation
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2022, Comparative Immunology, Microbiology and Infectious DiseasesQ fever prevention in Australia: general practitioner and stakeholder perspectives on preparedness and the potential of a One Health approach
2022, Australian and New Zealand Journal of Public HealthThe DNA-binding induced (de)AMPylation activity of a Coxiella burnetii Fic enzyme targets Histone H3
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