|Common Name(s)||Tularemia or Rabbit Fever|
|Scientific Name(s)||Francisella tularensis tularensis or Francisella tularensis holarctica|
|Physical Attributes||Gram-negative, short rod, aerobic bacilli; thin lipopolysaccharide-containing envelope|
|Geography||North America, Europe, Asia (China and Japan)|
|Mode(s) of Transmission||Bite of a insect- especially ticks and deerflies; contact with dead animals; eating and drinking contaminated food and liquids; inhalation|
|Likely BW Form(s)||Aerosol; contaminated food and water|
|Pathology||Sudden fever, chills, headaches, diarrhea, muscle aches, joint pain, dry cough, progressive weakness; sometimes develop chest pain, bloody sputum, and trouble breathing; also ulcers on the site of infection or mouth, swollen and painful lymph glands, swollen and painful eyes, and a sore throat|
|Host(s)||Humans, rodents, rabbits, hares|
|Vector/Dormant Form||Live for weeks in the soil; ticks; deerflies|
|Incubation Period||Typically 3-5 but ranges from 1-14|
|Fatality||Without treatment: type A at 5-15%, acute infection such as pneumoic and septic at 30-60%; type B: rarely fatal; weaponized fatality rates expected to be higher; with treatment, less than 2%|
|Vaccine||As of 2007, a vaccine is under review|
|Treatment||Antibiotics: tetracycline class (such as doxycycline) or fluoroquinolone class (such as ciprofloxacin) or streptomycin or gentamicin|
Tularemia, also known as "rabbit fever," is a disease caused by the bacterium Francisella tularensis. Francisella tularensis is a Gram-negative, nonmotile, enveloped coccobacillus. Tularemia is typically found in animals, especially rodents, rabbits, and hares. Tularemia is usually a rural disease and has been reported in all U.S. states except Hawaii, in China and Japan, and in Europe. Typically, people become infected through the bite of infected insects (most commonly, ticks and deerflies), by handling infected sick or dead animals, by eating or drinking contaminated food or water, or by inhaling airborne bacteria.
The bacteria can survive soil and water for weeks. It can survive for more than 3 years in frozen meat. There are seven different types of tularemia: ulceroglandular (most common at 45-80%, cutaneous ulcer), glandular, oculoglandular, oropharyngeal (ingestion), typhoidal, septicemia, and pulmonary (inhalation).
The incubation period for tularemia is typically 3 to 5 days, but can range from 1 to 14 days. The signs and symptoms people develop depend on how they are exposed to tularemia. Possible symptoms include skin ulcers, swollen and painful lymph glands, inflamed eyes, sore throat, mouth sores, diarrhea or pneumonia. If the bacteria are inhaled, symptoms can include abrupt onset of fever, chills, headache, muscle aches, joint pain, dry cough, and progressive weakness. People with pneumonia can develop chest pain, difficulty breathing, bloody sputum, and respiratory failure. Tularemia can be fatal if the person is not treated with appropriate antibiotics.
The fatality rate for typhoidal tularemia, the most virulent strain, is approximately 35% while ulceroglandular tularemia has a case fatality rate of 5%. With treatment, the fatality rate is low. Fatality rates with aerosolized tularemia in a biological attack are expected to be higher.
Early antibiotic treatment is recommended whenever it is likely a person was exposed to tularemia or has been diagnosed as being infected with tularemia. Several types of antibiotics have been effective in treating tularemia infections. The tetracycline class (such as doxycycline) or fluoroquinolone class (such as ciprofloxacin) of antibiotics are taken orally. Streptomycin or gentamicin are also effective against tularemia, and are given by injection into a muscle or vein. Health officials will test the bacteria in the early stages of the response to determine which antibiotics will be most effective. As of 2007, a vaccine is under review by the Food and Drug Administration and not yet available in the United States.
Francisella tularensis is very infectious. A small number (10-50 or so organisms) can cause disease. If Francisella tularensis were used as a weapon, the bacteria would likely be made airborne for exposure by inhalation. People who inhale an infectious aerosol would generally experience severe respiratory illness, including life-threatening pneumonia and systemic infection, if they are not treated. The bacteria that cause tularemia occur widely in nature and could be isolated and grown in quantity in a laboratory, although manufacturing an effective aerosol weapon would require considerable sophistication.
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