Rabbit Fever (Tularemia) in Dogs

Tularemia is a rare tick-borne illness. Dogs infected with the bacteria do not always develop symptoms, but the condition is highly contagious to humans. Hundreds of human cases are reported in the US each year. It is most common in the south central United States, the Pacific Northwest, and parts of Massachusetts.

Although dogs may not become seriously ill from tularemia, the fact that this disease is highly contagious and life-threatening to humans makes this a critical disease, and prompt veterinary attention is warranted for suspected cases. With proper treatment, the prognosis in dogs is good, although rarely, more serious cases can be fatal. If there is any reason to believe the dog has been exposed to potential risk factors such as tick bites or wild animals, tularemia should be suspected and careful precautions taken.

It is difficult to assess how many dogs are infected with F. tularensis each year since dogs rarely develop symptoms. Working dogs, hunting dogs, and those not on regular external parasite prevention are most at risk of infection by F. tularensis. Very young, elderly, and immunocompromised dogs are more at risk of developing symptomatic illness.

As tick bites are associated with tularemia, dogs may also present with tick infestation.

There are multiple subspecies of F. tularensis so the presentation of this disease varies greatly. Signs of tularemia also vary according to the mode of transmission.

A small number of dogs may die suddenly or shortly after exhibiting symptoms.

Tularemia is a bacterial infection caused by the organism Francisella tularensis. Dogs can become infected with the bacteria through:

• Ingestion of infected animal tissues (most common cause in dogs)
• Insect bites including ticks, fleas, mosquitoes, and biting flies
• Inhalation of aerosolized bacteria from outdoor activities including farming and landscaping
• Drinking contaminated water

If tularemia is suspected, immediate veterinary intervention is needed as careful handling protocols are needed. The first step in diagnosis is a complete physical exam. Next steps include blood work and urinalysis. Definitive diagnosis is usually reached by identification of organisms in tissue samples or blood culture. Diagnostic testing and sample collection may need to be performed at a specialized lab due to the highly contagious nature of the disease.

Treatment is with antibiotics and may involve supportive care (hospitalization, IV fluids, etc.). Mild cases may resolve on their own with only supportive care required. Prognosis with antibiotic treatment is good if initiated early. In more advanced cases, prognosis is guarded to poor.

Tularemia is very contagious from animal to animal (wildlife to dog) and from animal to human, but human-to-human transmission is rare. Prevention for dogs involves limiting exposure to wildlife and ticks. Tick repellant medications are recommended. Always consult a veterinarian before choosing external parasite control. Many available products are toxic to pets, especially cats. Reducing roaming behavior especially in dogs with a high prey drive is recommended. For humans, transmission potential can be limited by avoiding tick-infested areas, animal bites, scratches, face licking, and contact with carcasses dogs have retrieved.

Tularemia is very rare in dogs.

• Antibiotics
• Hospitalization with supportive care
• Surgical removal of abscesses