What is tularemia?
Tularemia is a bacterial disease caused by Francisella tularensis and is often referred to as rabbit fever. Tularemia is most commonly found in rabbits and rodents, and it survives by creating tumor-like masses and abscesses in the victim animal's liver. It is a disease that is not seen at all in the United Kingdom, Africa, South America, or Australia. In North America, tularemia cases are scattered around the continent. It is most commonly seen in the late spring and summer.
Tularemia is an uncommon infection in cats, but cats can be exposed if they kill or eat an infected rabbit or rodent or through insect bites.
How is tularemia transmitted?
Infection with Francisella tularensis can occur in several ways:
- Ingestion of the tissues or body fluids of an infected animal. After ingestion, the lymph nodes in the head, neck, and gastrointestinal system collect the bacteria. From there, systemic infection follows.
- Contaminated water.
- Some blood-sucking insects and arachnids including ticks, midges, fleas, or mosquitoes can transmit tularemia.
Once the bacteria are in the lymph system, the organism can be found in the lungs, liver, spleen, and the bone marrow.
What are the signs of tularemia infection in cats?
Tularemia generally causes an acute illness with high fever (40 - 41°C; 104 - 106°F), large painful lymph nodes in the head and neck, abdominal pain, jaundice (yellowing of skin, mucous membranes, and the whites of the eyes), and organ system failure.
How is tularemia diagnosed?
In order to diagnose tularemia, other diseases that cause sudden onset fever, enlarged lymph nodes, and lethargy must first be ruled out. These include bubonic plague and pseudotuberculosis.
Diagnostic tests typically include a complete blood count (CBC), a blood chemistry panel, and a urinalysis. Testing will reveal a high white blood cell count, low blood sugar, low blood sodium, and a high blood level of bilirubin. There may also be blood in the urine. Ultrasound may show masses in the internal organs including liver, spleen, or abdominal lymph nodes.
Blood tests done 2-4 weeks apart may demonstrate an increase in tularemia antibodies indicating infection. DNA testing (called PCR) may also identify tularemia in blood or tissue samples.
Can tularemia be treated?
Yes, tularemia can be treated, but it requires aggressive treatment including hospitalization with good supportive care (e.g., intravenous fluid therapy and antibiotics). The key to successful treatment is EARLY intervention. Even with early diagnosis and treatment, the death rate among cats with tularemia is high.
Can I catch tularemia?
Tularemia has a high zoonotic potential, meaning it can infect humans. Humans can become exposed from tick bites and drinking contaminated water; however, cat bites or scratches can also be a source of exposure. The bacteria create a blister in the skin 3-5 days after contact. The blister ulcerates 2- 4 days later, then the bacteria enter the lymph system, spreading to the rest of the body.
When hospitalized, these cats are isolated, and the veterinary team will wear protective gear during treatments. Tularemia is a reportable disease, meaning it is of such great public health importance that doctors and veterinarians are required to report diagnosis of the disease to their public health authority.