Tularemia
What is tularemia?
Tularemia is a disease
that humans typically acquire after skin or mucous membrane contact with tissues
or body fluids of animals infected with tularensis or from bites of infected
ticks, deerflies, or mosquitoes. Less commonly, inhalation of contaminated dusts
or ingestion of contaminated foods or water may produce clinical disease.
Respiratory exposure by aerosol typically causes typhoidal or pneumonic
tularemia. The germs can remain alive for weeks in water, soil, carcasses,
hides, and for years in frozen rabbit meat. It is resistant for months to
temperatures of freezing and below. It is easily killed by heat and
disinfectants.
What are the symptoms of tularemia?
After an incubation period
varying from 1-21 days (average 3-5 days), onset is usually acute. Tularemia
typically appears in one of several forms in man, depending upon the route of
inoculation:
- Ulceroglandular tularemia (75-85 percent of cases) is most often
acquired through infection of the skin or mucous membranes with blood or
tissue fluids of infected animals. It is characterized by fever, chills,
headache, malaise, an ulcerated skin lesion, and painful glands. The skin
lesion is usually located on the fingers or hand where contact occurs.
- Typhoidal tularemia (5-15 percent of naturally acquired cases)
occurs mainly after inhalation of germs. The germs would presumably be most
likely delivered by aerosol in a biological warfare attack and would primarily
cause this form of tularemia. It causes fever, prostration, and weight loss.
Pneumonia may be severe, and it is most common in typhoidal tularemia (80% of
cases). Respiratory symptoms, chest pain and a cough may also be present.
About 35% of untreated naturally acquired typhoidal cases die.
- Glandular tularemia (5-10 percent of cases) results in fever and
tender glands but no skin ulcer.
How is tularemia diagnosed?
A clue to the diagnosis of tularemia
subsequent to a biological warfare attack with F. tularensis could be a large
number of patients presenting with similar systemic illnesses and a
non-productive pneumonia in an area around the same time.
- The clinical presentation of tularemia may be severe, yet non-specific.
- X-rays show pneumonia or enlarged glands in the chest in typhoidal
disease. In general, chest radiographs show that approximately 50% of patients
have pneumonia.
- Laboratory tests are not very helpful.
- Tularemia can be diagnosed by recovery of the germ by cultures from blood,
ulcers, eyes, or sputum, even if the patient has been treated.
What is the treatment for tularemia?
Since there is no known
human-to-human transmission, neither isolation nor quarantine are required;
standard precautions are appropriate for care of patients with draining lesions
or pneumonia. Appropriate therapy includes one of the following antibiotics:
- Gentamicin
- Ciprofloxacin
- Streptomycin
Always consult your physician for more information.