Tularemia, also known as rabbit or deerfly fever, is an uncommon, though important, cause of fever in people and animals. Since the start of 2016, there have been two confirmed cases in local cats by the University of Minnesota.
What is tularemia?
Tularemia is a disease of both animals and people caused by a bacterium (Francisella tularensis).
How is tularemia spread?
- Tick and deerfly bites.
- Contact with infected animals. Most commonly hunting and skinning small mammals, like rabbits.
- Ingestion of contaminated meat or water.
- Inhalation of aerosols and dust while landscaping, farming or even mowing over deceased wildlife.
- Work place exposure (i.e. microbiologists, veterinary workers).
The incubation period is typically three to five days after exposure, though it can range from one to fourteen days.
What are the symptoms?
Cats with tularemia may develop a fever, mouth ulcers, enlarged lymph nodes, lethargy and poor appetite. Through research on natural and experimental infections, it appears that dogs can be infected with tularemia, though they rarely develop an illness. Infected dogs may develop a self-limiting fever, pimple/abscess at the site of infection and poor appetite.
While tularemia can be spread from animals to people, it is NOT contagious from person to person.
There are six different patterns of tularemia symptoms in people. They all involve a high fever (up to 104F). The most common form includes a skin sore at the site of the insect bite with swelling of nearby lymph nodes (this is called the ulceroglandular form). Other symptoms can include eye irritation/redness, sore throat, mouth ulcers, inflamed tonsils, muscle/joint pain, headache, and diarrhea. The most serious form (called the pneumonic form) involves a cough, chest pain and difficulty breathing from inhalation of the bacteria.
Click here to view a map of reported human cases in 2014.
How is it diagnosed?
- Growing (culturing) the bacteria is the test of choice, though it can take many days and requires special safety precautions due to the low number of bacteria needed to infect people with tularemia.
- Blood can be checked for antibodies to the bacteria (however; at the time of illness, it may be too early for antibody production which makes a recheck necessary in about three weeks).
- Tissue samples can be directly tested for DNA of the bacteria.
What is the treatment?
This section is simple… an appropriate class of antibiotics for about two to three weeks.
- Keep your cats indoors.
- Regularly use tick preventatives on pets, which can also protect your pet from more commonly transmitted tick diseases, such as Lyme, Anaplasma, Ehrlichia and others.
Check out this link for how to prevent yourself from contracting tularemia.
Even though tularemia is rare, some recreational activities may put you or your pet at higher risk of infection. If you’re concerned about your pet experiencing illness, please seek the advice of your family veterinarian. If you are experiencing flu-like symptoms, please seek the advice of your physician.
Looking for a bit more? Check out the FAQs from the Center for Disease Control (CDC).
Tularemia. JAVMA Vol 222, No 6. March 15, 2003.