Tularemia is a highly infective disease spread by the bacterium Francisella tularensis. Like other tick-borne infectious diseases, it is both preventable and treatable – but only if you’re aware of the risks. Read on to learn about what tularemia is, how it spreads, its symptoms and complications, and the most effective prevention and treatment methods.
What is tularemia?
Also known as rabbit fever, tularemia is an infectious disease that infects both animals and humans. Tularemia is spread by ticks and insects, contaminated water, food, or soil, and even bacteria that has been released into the air. Though a person can be infected by a relatively small amount of bacteria compared to other diseases, tularemia does not spread from person to person.
How Tularemia Spreads
In North America, tularemia is spread most commonly by the bacteria F. tularensis. However, there are three known subspecies outside the continent: F. tularensis holarctica in Europe and Asia, F. tularensis novocida, and F. tularensis mediaasiatica.
Below are some of the most common ways a person can be infected with tularemia:
- Tick bites or deer fly bites – Tularemia is known to be carried by the dog tick, wood tick, and lone star tick. Tularemia is also spread by deer fly bites, especially in the Western United States.
- Infected animals – These can be dead or alive, and are most often rabbits or hares. Both handling infected animal tissue and consuming undercooked meat from an infected animal can present risks of infection.
- Contaminated water or soil – Water and soil can become contaminated with tularensis from animals, then spread to people who consume or are directly exposed to it.
- Laboratory exposure – Whether through direct handling or inhalation, it is possible to contract tularemia from lab cultures if not using the proper protective equipment.
- Aerosol or dust inhalation – Bacteria released into the air through aerosolization or disturbed dust can and does spread tularemia.
Tularemia is considered a serious bioterrorist threat (PDF) due to its high infectivity and easy aerosolization.
Tularemia Symptoms and Complications
Tularemia symptoms are somewhat dependent on the mode of infection. According to the Centers for Disease Control and Prevention (CDC), some of the most common tularemia symptoms and the transmission types they accompany include:
- Fever – All forms and transmission types are associated with high fevers, some of which can reach 104 degrees F.
- Ulcers at the infection site – Also known as ulceroglandular tularemia, this is the most common form of tularemia, and is most often present when disease is spread by ticks or deer flies. Common symptoms are skin ulcers around the bite accompanied by the swelling of nearby lymph nodes. Ulceroglandular tularemia can also result from handling infected animal tissue (ulcers appear at the site where the bacteria entered the body).
- Swelling of lymph glands – Called glandular tularemia, this usually accompanies tick and fly bites or infection due to animal handling. As with ulceroglandular tularemia, the most common symptom is swelling of regional lymph nodes such as those in the armpits or groin.
- Irritation and inflammation of the infection site – This is most common in oculoglandular (infection through the eye) and oropharyngeal (infection through consumption of contaminated meat or water) tularemia. In oculoglandular forms, swelling of the lymph glands in front of the ear is usually accompanied by itching or redness of the eye. Oropharyngeal tularemia often results in sore throat, mouth ulcers, tonsillitis, and swelling of lymph glands in the neck.
- Pneumonia – According to the CDC, pneumonic tularemia is the most severe form of the disease and can be caused by either (1) inhalation of infected aerosols or dust, or (2) untreated ulceroglandular tularemia, which can cause the bacteria to spread to the lungs. Symptoms are consistent with other forms of pneumonia, including chest pain, coughing, and difficulty breathing.
The CDC recognizes typhoidal tularemia as a combination of any of the above general symptoms, without localizing symptoms.
Is tularemia fatal?
Yes, tularemia can be fatal if left untreated. But lesser – yet still very serious – complications are also possible. Other complications of untreated tularemia include meningitis (infection around the brain and spinal cord), pericarditis (inflammation of the heart), and osteomyelitis (infection of the bones).
Who is at risk for tularemia?
Anyone, anywhere, at any age can be infected with tularemia. In fact, tularemia has been reported in the United States, Canada, Mexico, Japan, and Europe.
However, there are certain risk factors that make some people more vulnerable to the disease, including:
- Working in hunting and trapping, because hunters are exposed to wild animal blood
- Working as gardeners and landscapers, because one can be infected by inhaling bacteria that are stirred up in the soil
- Working in wildlife management or veterinary medicine, where one can be exposed to either ticks and deer flies or infected animal tissue
The CDC offers several recommendations for preventing tularemia, such as:
- When landscaping, never mow over animal carcasses
- Using gloves when butchering or otherwise handling trapped or hunted animals
- Always cooking game meat thoroughly before eating
- Avoiding drinking untreated surface water while hiking and camping
- Practicing good tick prevention habits while hiking and camping
Because tularemia can also be contracted in a laboratory setting, it’s also crucial that lab workers follow all lab safety protocols and wear the proper protective equipment when handling bacteria cultures.
How is tularemia treated?
Like many other tick-borne infectious diseases, the most common tularemia treatment is antibiotics, such as streptomycin, gentamicin, doxycycline, and ciprofloxacin. However, also like other tick-borne diseases, tularemia can be difficult to diagnose – especially when left untreated and symptoms become less localized or specific.
If you think you’ve been exposed to tularemia, it’s imperative that you talk to your health care provider about getting tested.
One of many tick-borne diseases
Though Lyme disease gets a lot of attention, it is only one of many serious tick-borne diseases – including tularemia. As the medical community learns more and more about these diseases, their diagnosis, and their treatments, it has also gained a deeper understanding of the threat of several coinfections that can complicate the diagnosis and treatment of your tick-borne illness.
