Tularemia

What Is It?

Also known as "rabbit fever" or "deer fly fever," and caused by the francisella tularensis bacterium, tularemia is one of the most infectious diseases known, making it a strong bioweapon candidate. Although it's neither easy to disseminate nor lethal, it takes only the inhalation of a single tularemia bacterium to cause an infection. Tularemia is a rural disease and occurs in all states except Hawaii. It is widespread among animals, who are also a common source of transmission. Approximately 200 cases of tularemia in humans are reported annually in the United States, mostly in persons living in the south-central and western states. Tularemia is not contagious.

On a historical note, Ken Alibek, a former top Soviet bioweapons scientist, maintains that an outbreak of tularemia among German troops during the 1942 Battle of Stalingrad resulted from the deliberate spraying of the agent by the Soviet defenders.

How Is It Spread?

This agent can be transmitted either through aerosol form or via inhalation. The natural ulceroglandular form of this infection is typically contracted through the bite of an infected tick or fly, or when infected meat has direct contact with an open wound. Tularemia infection can also occur when someone eats undercooked, infected meat.

What Are the Symptoms of Exposure?

If released in aerosol form, inhaled tularemia could cause severe pneumonia. Symptoms would include shortness of breath, coughing up bloody mucus and chest pain. The usual incubation period for inhaled tularemia is 3-5 days, but can be as short as one day or as long as two weeks. Initial symptoms include fever, chills, coughing, joint pain, headaches and weakness - much like that of the common cold or influenza.

A small percentage of those infected with inhaled tularemia will develop the typhoidal form of the bacterium instead of pneumonia, which hones in on the circulatory system instead of just the respiratory system and may lead to death if not promptly treated. This type of illness is characterized by fever, extreme exhaustion and weight loss and the fatality rate of those untreated is 35 percent.

Ulceroglandular tularemia causes an ulcer at the infection site and later swelling of regional lymph nodes. This form has a lower fatality rate than pneumonic or typhoidal tularemia.

How Is It Treated?

Tularemia is easily treatable with antibiotics, as long as victims get treatment quickly. A vaccine exists, but is currently administered only to individuals who work with the bacterium. The vaccine takes about two weeks to fully protect a human being and isn't completely effective against the inhaled form of tularemia. Another vaccine to protect against inhaled tularemia is being developed.

After potential exposure or diagnosis, early treatment is recommended with an antibiotic from the tetracycline (such as doxycycline) or fluoroquinolone (such as ciprofloxacin) class, which are taken orally, or the antibiotics streptomycin or gentamicin, which are given intramuscularly or intravenously.

Who Has It/Where Can It Be Found?

Isolating and growing the tularemia bacterium takes a lot of experience and scientific knowledge. The former Soviet Union, Japan and the United States all developed the bacterium as a bioweapon, and the former U.S.S.R. continued its research into the 1990s. Many of those supplies and scientists haven't yet been located. Tularemia does occur naturally in rodents.