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Bioterrorism

Profiles for Health Care Workers (Fact Sheets) - "B" Agents

  • Health Care Providers: If you suspect a patient has been exposed to a biological or chemical agent please call the Office of Infectious Disease Services at (602) 364-4562
    On-call staff are available 24 hours a day, 7 days a week.

Brucellosis | Cholera | (Epsilon Toxin of) Clostridium Perfringens | Cryptosporidiosis | Eastern Equine Encephalitis
Escherichia Coli O157:H7 | Glanders | Melioidosis | Psittacosis | Q Fever | Ricin | Salmonellosis
Shigellosis | Staphyloccal Enterotoxin B | Tricothecene Mycotoxins (T-2 Mycotoxins)
Typhus Fever | Venezuelan Equine Encephalitis | Western Equine Encephalitis

Q Fever

Causative Agent:
Q fever is a zoonotic disease caused by a rickettsia Coxiella burnetii.

Route of Exposure:
Humans usually acquire Q fever through the inhalation of airborne particles. Sheep, cattle, and goats can serve as reservoirs for the agent. Consumption of contaminated food or water can also result in infection.

Infective Dose & Infectivity:
1-10 Organisms

Incubation Period:
The incubation period ranges from 10 to 40 days.

Clinical Effects:
Q fever generally occurs as a self-limiting illness lasting 2 days to 2 weeks. The disease generally presents as an acute non-differentiated febrile illness with headaches, fatigue and myalgias as prominent symptoms. Pneumonia with an abnormal chest X-ray occurs in about 50% of all patients. Non-productive cough and pleuritic chest pain can also occur. Uncommon complications of Q fever infection include: chronic hepatitis, endocarditis, aseptic meningitis, encephalitis, and osteomyelitis.

Lethality:
While highly incapacitating, the death rate due to Q fever is very low (<1-3%).

Transmissibility (person to person):
Transmission from person-to-person is extremely rare.

Primary Contamination & Methods of Dissemination:
The most likely route of intentional dissemination would be through aerosolization. Alternatively, the organism could be disseminated through sabotage of the food supply.

Secondary Contamination & Persistence of Organism:
Persons who are exposed to Q fever through the aerosol route do not present a risk for secondary contamination or re-aerosolization of the organism. The organism is highly resistant to many disinfectants.

Decontamination & Isolation:

  • Patients – Patients can be treated using standard precautions. Gross decontamination is not necessary.
  • Equipment & other objects – Contaminated surfaces and clothing can be decontaminated with 0. 5% hypochlorite solution (one part household bleach and nine parts water = 0.5% solution) or a 1:100 solution of Lysol.

Outbreak control: Since secondary cases are unlikely, outbreak control measures are not recommended.

Laboratory Testing:
Isolation of C. burnetii is usually not done due to the risk to laboratory workers. Diagnosis can be made acute and convalescent antibody titers (indirect immunofluorescence antibody or complement fixation antibody), polymerase chain reaction on tissue, or positive immunostaining on a heart valve.

Therapeutic Treatment:
Tetracycline or doxycycline is the recommended treatment. A combination of erythromycin plus rifampin is also effective.

Prophylactic Treatment:
Treatment with a tetracycline during the incubation period may delay, but will not prevent the onset of symptoms. A vaccine has been developed, but is not licensed for use in the United States.

Differential Diagnosis:
Q fever must be differentiated from pneumonias caused by mycoplasma, Legionella pneumophila, Chlamydophila psittaci, or Chlamydophila pneumoniae.

References:

  • Committee on Infectious Diseases. Q Fever. In: Pickering LK, ed. Red Book: 2003 Report of the Committee on Infectious Diseases. Elk Grove Village, IL: American Academy of Pediatrics; 2003: 512-514.
  • Chin J. Control of Communicable Diseases Manual, Seventeenth Edition, American Public Health Association; 2000.
  • Kortepeter M, Christopher G, Cieslak T, et al. Medical Management of Biological Casualties Handbook, U.S. Army Medical Research Institute of Infectious Diseases, U.S. Department of Defense; 2001: 33-36.
  • Byrne WR. Q Fever. In: Zajtchuk R, Bellamy RF, eds. Medical Aspects of Chemical and Biological Warfare. Washington, DC: Office of the Surgeon General, U.S. Department of the Army; 1997: 523-537.


Find the PDF version of this Fact Sheet in the Zebra Manual.