Tularemia

Tularemia

Do Rabbits Cause Rabbit Fever?

How Do People Contract Rabbit Fever?

Is Tularemia Common?

What Are the Symptoms of Tularemia?

How Can a Doctor Tell if a Person Has Tularemia?

How Is Tularemia Treated?

Is There Any Way to Prevent Tularemia?

Resources

Tularemia (too-lah-REE-me-uh), sometimes called rabbit fever, is an infection caused by bacteria that can be spread to humans by wild animals.

KEYWORDS

for searching the Internet and other reference sources

Biological weapons

Bioterrorism

Francisella tularensis

Rabbit fever

Tick-borne diseases

Zoonoses

Do Rabbits Cause Rabbit Fever?

Tularemia is caused by the bacterium Francisella tularensis (fran-sih-SEL-uh too-lah-REN-sis). Most cases in the United States come from contact with infected rabbits and deer, although the bacterium also lives in other small mammals and birds, and it can be found in soil.

Tularemia bacteria enter the body through the mucous membranes*, the skin, the lungs, or the digestive system. There are seven different forms of the disease:

*mucous membranes

are the moist linings of the mouth, nose, eyes, and throat.

• Ulceroglandular tularemia comes from handling an infected animal or from the bite of a tick or deer fly. An ulcer (an open sore) forms on the skin.
• Glandular tularemia causes symptoms similar to those of the ulceroglandular form but an ulcer does not form. The bacteria may enter the body through small cuts in the skin. Most cases of rabbit fever in the United States are glandular or ulceroglandular tularemia.
• Oculoglandular tularemia comes from touching the eye with infected fingers. The eye becomes red and painful and has a discharge.
• Oropharyngeal tularemia comes from eating the undercooked meat of an infected animal or from drinking water contaminated by the bacterium. It causes digestive system symptoms, such as vomiting or diarrhea.
• Pneumonic tularemia is caused by inhaling spores (an inactive form of the germ enclosed in a protective shell) in dust from a contaminated area into the lungs. Other types of tularemia also may spread to the lungs.
• Typhoidal tularemia affects many organs of the body. This rare form of the disease occurs without any previous signs of infection in any specific part of the body.
• Septic tularemia is a severe form of the disease that affects the whole body. Someone with this form may go into shock* and experience serious complications.

*shock

is a serious condition in which blood pressure is very low and not enough blood flows to the body’s organs and tissues. Untreated, shock may result in death.

Is Tularemia the Next Anthrax?

It takes as few as 10 spores of the Francisella tularensis bacterium to infect someone with tularemia. The bacterium is hard to destroy and can be easily released into the air. For these reasons, experts on biological warfare fear that some groups might use tularemia as a weapon.

The United States stockpiled the bacteria during the 1960s but destroyed its stores in the 1970s at the order of the president. Russia, too, stockpiled and produced the bacteria through the mid-1990s.

There is no vaccine currently available in the United States. In the event of a bioterrorist attack, swift and widespread use of antibiotics could reduce the harmful effects of the disease.

How Do People Contract Rabbit Fever?

People cannot catch tularemia from one another. Most cases in the United States occur when someone gets a bite from a tick or deer fly that has previously bitten an infected rabbit or deer. Those in contact with infected animals may be infected by the bacterium through small cuts on the skin. Hunters contract tularemia from handling or eating undercooked, contaminated meat. In rare cases, bacterial spores survive in the soil and are released into the air; people then breathe the spores into their lungs. Drinking contaminated water is another rare but possible way to contract the disease.

Is Tularemia Common?

Tularemia occurs in the United States, Europe, and Asia, mainly in rural areas. Tularemia is highly infectious, but in the United States fewer than 200 cases are reported each year (mostly from Texas, Arkansas, and Oklahoma). Some additional cases may not be recognized and reported.

Tularemia affects people of every age, sex, and race. In spring and summer months, it occurs most often in children who become infected when playing outside. In fall and winter, hunters are more likely to contract the infection.

What Are the Symptoms of Tularemia?

Symptoms of tularemia depend on the form of the disease. Most infected people have a red spot at the site of the insect bite or cut where the bacterium entered the body. This becomes an ulcer.

Other signs and symptoms appear within 1 to 14 days (most frequently in 2 to 5 days) and may come on suddenly. They can include extreme tiredness, muscle aches, fever, headache, sweating, chills, and weight loss. Lymph nodes* in the groin and armpits may become swollen.

*lymph

(LIMF) nodes are small, bean-shaped masses of tissue that contain immune system cells that fight harmful microorganisms. Lymph nodes may swell during infections.

People who contract tularemia from inhaled bacteria usually have pneumonia*-like symptoms, such as a dry cough, shortness of breath, or discomfort in the chest area. This form can progress to shock and respiratory failure*.

*pneumonia

(nu-MO-nyah) is inflammation of the lung.

*respiratory failure

is a condition in which breathing and oxygen delivery to the body is dangerously altered. This may result from infection, nerve or muscle damage, poisoning, or other causes.

People who drink contaminated water or eat contaminated meat may experience nausea (NAW-zee-uh), vomiting, pain in the abdomen, diarrhea, sore throat, and sometimes gastrointestinal* bleeding.

*gastrointestinal

(gas-tro-in-TES-tih-nuhl) means having to do with the organs of the digestive system, the system that processes food. It includes the mouth, esophagus, stomach, intestines, colon, and rectum and other organs involved in digestion, including the liver and pancreas.

How Can a Doctor Tell if a Person Has Tularemia?

Doctors use blood tests to check for tularemia. Some tests look for antibodies* to the Francisella tularensis bacterium. Doctors also may look for evidence of the bacterium in the blood, fluid from the nose and mouth, and lymph nodes. If the person has symptoms of pneumonia, a chest X ray will be taken.

*antibodies

(AN-tih-bah-deez) are protein molecules produced by the body’s immune system to help fight specific infections caused by microorganisms, such as bacteria and viruses.

How Is Tularemia Treated?

Tularemia responds well to antibiotics, and most people can receive treatment at home. Because tularemia is not contagious, people who have it do not have to be isolated.

In more severe cases, when the disease attacks the lungs or other organs, people may require hospitalization and closer monitoring.

Most people who receive treatment recover from tularemia. The septic and pneumonic forms of the disease can be life threatening, however. Symptoms of tularemia can last for several weeks. Most people do not experience any lasting damage from the disease and may develop some degree of immunity* to it.

*immunity

(ih-MYOON-uh-tee) is the condition of being protected against an infectious disease. Immunity often develops after a germ is introduced to the body. One type of immunity occurs when the body makes special protein molecules called antibodies to fight the disease-causing germ. The next time that germ enters the body, the antibodies quickly attack it, usually preventing the germ from causing disease.

Complications of tularemia can include pneumonia, meningitis*, osteomyelitis*, kidney problems, lung abscesses*, pericarditis (inflammation of the sac surrounding the heart), shock, and, rarely, death.

*meningitis

(meh-nin-JY-tis) is an inflammation of the meninges, the membranes that surround the brain and the spinal cord. Meningitis is most often caused by infection with a virus or a bacterium.

*osteomyelitis

(ah-stee-o-my-uhLYE-tis) is a bone infection that is usually caused by bacteria. It can involve any bone in the body, but it most commonly affects the long bones in the arms and legs.

*abscess

(AB-ses) is a localized or walled off accumulation of pus caused by infection that can occur anywhere in the body.

Is There Any Way to Prevent Tularemia?

In the past, laboratory workers at risk for contracting tularemia because of frequent contact with laboratory animals were vaccinated against the disease. In 2003, the vaccine is not available for public use in the United States while the Food and Drug Administration performs further studies.

The best way to avoid contracting tularemia is to prevent tick bites by using repellent and wearing light-colored clothing that covers arms and legs. It is wise to avoid contact with certain wild animals, such as rabbits. Experts recommend that hunters wear rubber gloves when handling animals and that all meat be thoroughly cooked. Swimming in or drinking water that might be contaminated should be avoided.

See also

Bioterrorism

Meningitis

Osteomyelitis

Pneumonia

Tick-borne Infections

Zoonoses

Resources

Organizations

American College of Emergency Physicians, 1125 Executive Circle, Irving, TX 75038. The American College of Emergency Physicians provides advice about avoiding tick bites in the article “Tick Bites—They’re Not Just About Lyme Disease” posted at its website.

Telephone 800-798-1822 http://www.acep.org

U.S. Centers for Disease Control and Prevention (CDC), 1600 Clifton Road, Atlanta, GA 30333. The CDC is the U.S. government authority for information about infectious and other diseases. It has a web page explaining tularemia and how it can be used as a biochemical weapon.

Telephone 800-311-3435 http://www.cdc.gov