Tularemia - Francisella tularensis Infection
Tularemia is caused by the bacteria Francisella tularensis. Tularemia occurs after the skin or mucous membranes come in contact with tissues or body fluids of infected animals, or from bites of infected ticks, deerflies, or mosquitoes. In addition, inhalation of contaminated dusts or ingestion of contaminated foods or water may cause clinical disease.

Tularemia as a Weapon
The bacteria Francisella tularensis can remain infective in water, soil, carcasses hides, and frozen meat. However, the bacteria is easily killed by heat and disinfectants. Francisella tularensis was weaponized by the United States in the 1950's and 1960's during the US offensive biowarfare program. Other countries are suspected to have weaponized this agent.

Tularemia Symptoms
The incubation period of tularemia varies from 1 to 21 days. Only 1 to 10 organisms are required to cause disease. There are six forms that occur in humans depending on the route of inoculation.

Ulceroglandular Tularemia

• Occurs after inoculation of skin with infected fluids
• Symptoms include fever, chills, headache, fatigue, swollen lymph nodes, and an ulcerated skin lesion
• Usual location of the ulceration is the hand or fingers
• Accounts for 45% to 80% of tularemia cases
• Fatal in 5% of cases if not treated

Glandular Tularemia

• Same symptoms as the ulceroglandular form, but without the skin lesions
• Accounts for 10% to 25% of tularemia cases

Oculoglandular Tularemia

• Occurs after inoculation of the eyes by contaminated hands, splattering of infected tissue fluids, or by aerosols
• Symptoms occur in one eye and include pain, redness, and yellow discharge with swollen lymph nodes
• Accounts for <5% of tularemia cases

Oropharyngeal Tularemia

• Symptoms of ulceroglandular tularemia confined to the throat - sore throat and swollen lymph nodes
• Accounts for <5% of tularemia cases

Typhoidal Tularemia

• The most likely form to be caused by an aerosolized bioterror weapon
• Symptoms include fever, cough, chest pain, and shortness of breath
• Fatality following a bioterrorist attack is unknown
• Normally fatal in 35% of naturally occurring disease if not treated

Pneumonic Tularemia

• Also a possible bioterrorism form
• Occurs after inhalation of organisms or spread of bacteria to the bloodstream
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• ymptoms are consistent with a severe, atypical pneumonia
• Fatality is unknown but expected to be high

Treatment of Tularemia
Tularemia is treated with antibiotics. Initial treatment consists of intravenous gentamicin or ciprofloxacin. After clinical improvement oral antibiotics may be used, most commonly streptomycin, gentamicin, or tetracycline. Initial studies show that treatment of tularemia exposure with ciprofloxacin or doxycycline within the first 24 hours of aerosol exposure protects against the disease. A vaccine is currently under development and has shown promise in protecting against active disease.

Information for this article was taken from:
- www.cdc.gov Facts About Tularemia
- Darling RG, et al - Threats in bioterrorism I: CDC category A agents - Emergency Medicine Clinics of North America; May 2002; vol 20(2).
- Miller JM - Agents of Bioterrorism: Preparing for Bioterrorism at the Community Health Care Level - Infectious Disease Clinics of North America; Dec 2001; vol 15(4).
- Noah DL, et al - The history and threat of biological warfare and terrorism - Emergency Medicine Clinics of North America; May 2002; vol 20(2).