What is tularemia?
Tularemia, also known as "rabbit fever," is a potentially serious disease caused by the bacterium Francisella tularensis. Tularemia occurs naturally and is typically found in warm-blooded animals, especially rodents, rabbits and hares. It is also found in voles, muskrats, beavers, and some domestic animals. The organism can also be found in hard ticks. It is usually a rural disease and has been reported in all the U.S. states except Hawaii.
How do people become infected with tularemia?
Typically, people become infected through the bite of infected insects (most commonly, wood ticks, dog ticks, lone star ticks, and deerflies), by handling infected sick or dead animals (e.g. during skinning or dressing), by eating or drinking contaminated food or water, by handling or eating undercooked meats of infected animals, by breathing in dust from infected soil, grain, or hay or by inhaling airborne bacteria.
Tularemia is not known to be spread from person to person. People who have tularemia do not need to be isolated. People who have been exposed to the tularemia bacteria should be treated as soon as possible. The disease can be fatal if it is not treated with the right antibiotics.
Does tularemia occur naturally in the United States?
Yes. Tularemia is a widespread disease in animals. About 200 human cases of tularemia are reported each year in the United States. Most cases occur in the south-central and western states. Nearly all cases occur in rural areas and are caused by the bites of ticks and biting flies or from handling infected rodents, rabbits, or hares. Cases also resulted from inhaling airborne bacteria and from laboratory accidents.
What are the signs and symptoms of tularemia?
Signs and symptoms people develop depend on how they were exposed to tularemia. The incubation period (the time from being exposed to becoming ill) is typically 3 to 5 days, but it can range from 1 to 14 days. Symptoms of tularemia could include:
- slowly developing sore at the site of the bite
- sudden fever
- chills
- headaches
- diarrhea
- muscle aches
- joint pain
- dry cough
- progressive weakness
- skin ulcers
- swollen and painful lymph nodes
- inflamed eyes
- sore throat
- mouth sores
People can also catch pneumonia and develop chest pain, difficulty breathing, bloody sputum, and respiratory failure.
If the bacteria are inhaled, symptoms can include:
- abrupt onset of fever
- chills
- headache
- muscle aches
- joint pain
- dry cough
- progressive weakness
- stomach pain
- vomiting
Tularemia can be fatal if the person is not treated with appropriate antibiotics.
What should someone do if he or she suspects exposure to tularemia bacteria?
If you suspect you were exposed to tularemia bacteria, see a doctor quickly. Treatment with antibiotics for a period of 10-14 days or more after exposure may be recommended. If you are given antibiotics, it is important to take them according to the instructions you receive. All the medication you are given must be taken. Be sure to let the doctor know if you are pregnant or have a weakened immune system.
Local and state health departments should be notified immediately so an investigation and infection control activities can begin.
How is tularemia diagnosed?
When a person has symptoms that appear related to tularemia, the healthcare worker collects specimens, such as blood or sputum, for testing in a diagnositc or reference laboratory. Laboratory test results for tularemia may be presumptive or confirmatory. Presumptive (preliminary) identification may take less than 2 hours, but confirmatory testing will take more time, often 24 to 48 hours or longer depending on the methods that need to be used.
Depending on the cirucumstances, a person may be given treatment based on symptoms before the laboratory results are returned.
Can tularemia be effectively treated with antibiotics?
Yes. 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.
How long can Francisella tularensis exist in the environment?
Francisella tularensis can remain alive for weeks in water and soil.
Is there a vaccine available for tularemia?
A vaccine for tularemia was used in the past to protect laboratory workers, but it is not currently available.
What can I do to prevent becoming infected with tularemia?
Tularemia occurs naturally in many parts of the United States.
- Avoid areas infested with ticks and mosquitoes.
- Use insect repellents and wear protective clothing when outdoors (long pants and long-sleeved shirts; tuck pant legs into socks, and tuck shirt into pants).
- Inspect your entire body (head to toe) for ticks after being outdoors.
- Remove attached ticks by grasping the tick close to the skin surface and pulling straight back with a steady force; use pointed tweezers to grasp the tick. If fingers must be used, protect hands by using gloves, cloth,or tissue. Do not squeeze the tick's body or use petroleum jelly, lighted cigarettes or matches, or alcohol. Clean the bite site after removing a tick and then wash your hands.
- Wear gloves when handling (e.g. skinning or dressing) carcasses of dead animals, especially rabbits, squirrels and rodents. Wash hands thoroughly after handling animal carcasses.
- Cook all wild animal meat, such as rabbit or squirrel, until well done.
- Wash hands thoroughly after working with soil, before and after handling foods, and before eating.
- Do not drink, bathe, swim, or work in untreated water areas where infected wild animals may have been.
- Note any change in the behavior of your pets (especially rodents, rabbits, and hares) or livestock, and consult a veterinarian if they develop unusual symptoms.
Can tularemia be used as a weapon?
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 would 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.
What is CDC doing about tularemia?
The CDC operates a national program for bioterrorism preparedness and response that incorporates a broad range of public health partnerships. Other things CDC is doing include:
- stockpiling antibiotics to treat infected people
- coordinating a nation-wide program where states share information about tularemia
- creating new education tools and programs for health professionals, the public, and the media