Time to Watch for Tularemia
By Dr. Sasha Thomason
Spring has finally arrived! For those of us in the veterinary medical profession, that also means ticks, fleas and certain diseases are arriving as well. Tularemia is one of those diseases.
Tularemia is a highly contagious, acute onset bacterial infection caused by the organism, Francisella tularensis. It affects many mammalian and avian species and is endemic in the United States, as well as most of the Northern hemisphere. Important animal sources of infection in Kansas include the cottontail rabbit, wild hares, and rodents.
Cats are the most commonly affected companion animals. Symptoms in cats can be life-threateningly severe and include acute onset of fever, swollen lymph nodes, depression, lethargy and inappetence. Hospitalization for treatment and supportive care is usually needed. Dogs seem to be relatively resistant to infection and tend to show no symptoms or only mild symptoms. The incubation period in animals ranges from 1 to 10 days.
There are a variety of ways to contract this disease:
- Tick bites
- Biting flies
- Penetrating injuries, open wounds
- Contaminated water exposure
- Contaminated food exposure
Diagnostic testing is available to aid in diagnosis, with some special instructions:
- Diagnostic Test of Choice: Isolation/Culture of organism from affected tissue or exudates
- Sample Needed: An aspirate of an affected lymph node is preferred. An aspirate of the spleen can also be cultured, but this is less ideal because of the increased risk of exposure to the organism. If the diagnosis is needed on a patient post-mortem, send the whole cat to minimize your exposure to tularemia.
- Test Selection: Aerobic Culture (BAC-0100) **Be sure to mark that you suspect Tularemia on the paperwork as it is a select agent.**
- Important Additional Info: It is a select agent. KSVDL will perform the initial testing here. We have to send any suspect positives to the CDC for confirmatory testing which usually increases the turnaround time by 1- 2 days.
- Not usually clinically affected
- If active infection suspected, same as for Cats
- The KSVDL will do the same type of testing on wildlife/other animals that are Tularemia suspects. Send in the whole body for testing. Animals tested in the past by KSVDL: rabbits, monkeys
PUBLIC HEALTH CONSIDERATIONS:
Always remember to inform your clients that this is a zoonotic, highly contagious disease. The CDC recommends wearing gloves when handling tularemia-suspect patients and any body fluids or diagnostic samples collected. The CDC also recommends disinfecting any clothing or linens that have become contaminated with body fluids from a tularemia patient by using standard hospital procedures.
For humans, tularemia is a reportable disease in all states, including Kansas, because of its select agent status. Its high infection rate, multiple routes of transmission and the severity of illness it causes has led to its classification as a possible agent of bioterrorism.