Tularemia is an infectious disease that typically infects:
- wild rodents
Humans can become infected by having direct contact with an infected animal or from tick, mosquito, or deer fly bites. The disease is caused by the bacterium Francisella tularensis. It can be life-threatening.
The various forms of tularemia are distinguished by where the bacteria enter the body. The most common form of the disease is caused by skin contact with the bacteria. The deadliest form of the disease is caused by inhaling the bacteria.
Tularemia can often be treated with antibiotics. Early treatment offers a good outlook for complete recovery. However, some severe cases may be fatal even with treatment.
Tularemia is rare. There are usually 100 to 200 reported cases in the United States each year.
The symptoms vary depending on where the bacteria enters your body.
The symptoms of ulceroglandular tularemia, or infection through the skin, can include:
- a skin ulcer at the point of contact with the infected animal or at the site of a bite
- swollen lymph nodes near the skin ulcer (most often in the armpit or groin)
- severe headaches
- a fever
The symptoms of glandular tularemia, or infection through the skin, are similar to ulceroglandular symptoms but without a skin ulcer.
Pneumonic tularemia is the deadliest form of this disease. It’s transmitted through inhalation. The symptoms can include:
- a dry cough
- breathing difficulty
- a high fever
- chest pain
The symptoms of oculoglandular tularemia, or infection of the eye, can include:
- eye irritation
- eye pain
- eye swelling
- discharge or redness of the eye
- a sore on the inside of the eyelid
- swollen lymph glands behind the ear
The symptoms of oropharyngeal tularemia, or infection through ingestion of the bacteria, can include:
- a sore throat
- ulcers in the mouth
- swollen lymph nodes in the neck
- tonsillitis, or swollen tonsils
The symptoms of the rarest form of this disease, typhoidal tularemia, can include:
- a very high fever
- extreme fatigue
Typhoidal tularemia can lead to pneumonia and an enlarged liver and spleen.
Severe and untreated cases of tularemia may cause:
- chronic heart failure
- swelling of the membranes that surround your brain and spinal cord, which is called meningitis
The bacterium F. tularensis causes tularemia. Creatures capable of carrying the bacteria include:
- rabbit and deer ticks
- grizzly bears
- cats that go outdoors
Which type of tularemia you develop depends on how the bacteria enters your body. Skin exposure is the most common form of the disease. Inhalation through the lungs is the deadliest form of tularemia. If it’s left untreated, other forms of the disease may eventually reach the:
- spinal cord
The disease can cause serious complications and sometimes death.
The route of entry and resulting forms of tularemia include the following:
- Skin exposure causes glandular or ulceroglandular tularemia.
- Inhalation of aerosolized bacteria causes pneumonic tularemia.
- Exposure through the eye causes oculoglandular tularemia.
- Ingestion causes oropharyngeal tularemia.
- Systemic infection causes typhoidal tularemia.
Animals carry the bacteria that causes tularemia. You’re at increased risk of getting the disease if you have frequent contact with animals.
People at an increased risk for tularemia include:
- those who work closely with animals, such as veterinarians, zookeepers, and park rangers
- those who live in heavily forested areas
- those who work with animal carcasses, such as hunters, taxidermists, and butchers
- those who work in gardening and landscaping
Diagnosing tularemia isn’t easy because it can often appear like other diseases. The various possible routes of entry of the bacterium complicates the issue. Your doctor must rely heavily on a your personal and medical history to help diagnose you.
Your doctor may suspect tularemia if you’ve had recent travels, insect bites, or contact with animals. They may also suspect that you have this disease if you already have a serious medical condition that compromises your immune system, such as cancer or HIV or AIDS.
Tests for the presence of this disease include:
- a serology test for antibodies your body has created to fight the bacteria
- a pleural fluid test, which tests the fluid from the pleurae in the chest cavity
- a skin biopsy of a lesion and microscopic exam looking for the presence of tularemia
- a lymph node biopsy, which is the removal of tissue from a lymph node for examination
- a bone marrow biopsy, which is the removal of a sample of bone marrow for examination
Each case of tularemia is treated according to its form and severity. Early diagnosis allows for immediate treatment with antibiotics.
Antibiotics that may be used to treat tularemia include:
- doxycycline (Vibramycin)
- gentamicin, which is usually used to treat oculoglandular tularemia
Surgical intervention may be required to drain swollen lymph nodes or to cut away infected tissue from a skin ulcer. You may also be given medications for fever or headache symptoms.
Your outlook depends on the severity of the condition and how quickly you start receiving treatment. Delays in diagnosis will cause a worsening of symptoms.
Hospitalization is common in many cases. The most severe type of the disease is pneumatic tularemia. About 2 percent of tularemia cases are fatal. Most of these are pneumatic tularemia cases.
Prevention involves taking basic safety precautions. The bacteria thrive in dirty conditions. Outbreaks of this disease have occurred in hunting parties when hunters failed to practice safe cleaning methods and contaminated their belongings.
To safely clean animals when hunting, you should take the following precautions:
- Don’t skin or dress (remove the organs of) any animal that appears to be sick.
- Wear gloves and goggles when handling any animal.
- Wash your hands carefully after handling an animal.
- Cook the meat thoroughly.
To decrease your overall risk of contracting tularemia, you should:
- Wear long pants and sleeves in the forest to help prevent tick bites.
- Keep animal remains away from food or water.
- Avoid drinking water from lakes or ponds.
- Protect your outdoor pets with flea and tick medicines.
- Use insect repellents.
Tularemia is easily aerosolized and can be a potentially deadly bioterrorism agent, although you’re much more likely to become infected from contact with an animal. You should talk to your doctor immediately if you think you might have tularemia.