Tularemia in Illinois

by Nelda A. Rivera, Nohra Mateus-Pinilla | August 1, 2025 | Wildlife

A close up of a brown and tan cottontail rabbit in short green grass.

Photo by Grayson Smith, USFWS.

Tularemia is a zoonotic disease that has recently re-emerged in parts of Illinois. Here’s an overview of this bacterial disease, along with tips on how to empower yourself to safely enjoy your outdoor adventures and protect your dogs and cats.

What do we need to know about Tularemia in Illinois?

Tularemia is a bacterial septicemia (blood poisoning) that can affect people and more than 250 species of wild and domestic mammals, fish, reptiles and birds in North America and Eurasia.¹ Rabbit fever or deer fly fever are other names for Tularemia, a classic zoonosis—a disease that can be transmitted from animals to humans. Humans can accidentally get infected via the skin while handling infected animals (e.g., dressing, preparing and improperly cooking wild game), ingestion of contaminated food or water, by inhaling dust or aerosols contaminated with Francisella tularensis bacteria, and from a vector bite such as ticks, mosquito and flies from the family Tabanidae.^1,2 It has been suggested that birds can also act as vectors, as they may not be infected but carry the bacteria in their claws or beak. For example, a case report of a female jogger who was attacked by a common buzzard (Buteo buteo) that resulted in light scratches on the back of the head, and the development of Tularemia.³ Several other joggers were also attacked around the same time; however, only one additional case of Tularemia was reported. ³

A flow chart indicating how people can get infected with Tularemia accidentally through the skin while handling infected animals, through the bite of infected animals, through consuming contaminated food or water, or by inhaling dust or aerosols contaminated with Tularemia bacteria. — **Figure 1**. In general, humans can become infected accidentally through the skin while handling infected animals, if bitten by infected vectors, consuming contaminated food or water, or by inhaling dust or aerosols contaminated with *F. tularensis* bacteria. Rodents and lagomorphs are particularly susceptible and can become common reservoirs among wildlife. Transmission from animal to animal may occur through cutaneous, respiratory, or gastrointestinal routes. Deer fly photo by xpda; Lone star tick and American dog tick photos from CDC. Cycle adapted from Sharma et al., 2023.

The bacteria (F. tularensis) can survive for weeks or months in moist environments. Still, the bacterium is an intracellular parasite that can be easily treated with antibiotics following a prompt visit to a doctor and is effectively killed by heat and bleach.^1,2

In August 2024, the Wildlife Medical Clinic at the University of Illinois reported noticing an increase in wild rabbits with Tularemia.⁴ Recently, in April 2025, case reports of Tularemia have emerged. Several cases of dead or ill squirrels were reported in Urbana, and a dead rabbit tested positive for Tularemia in central Illinois.⁵ While Tularemia can occur across the United States, it is not a common disease. When the incidence—the number of new cases of disease in a population over a specific period—increases, public health officials respond accordingly, providing recommendations for populations at risk.

Suggestions on how to reduce the risk of humans and pets becoming infected include:

A brown and gray cottontail rabbit rests under a bush. In the foreground are metal mesh cages around garden flowers to protect the plants from rabbit damage. — Photo by Sarah Marjanovic.

Do not handle wild animals.
Avoid mowing over dead animals. Moreover, inspect the area before mowing to avoid accidents with other animals.
Do not allow dogs and cats to roam outdoors unsupervised as they may hunt or eat carcasses and drink water that may be contaminated with bacteria.
Take any pet showing signs of Tularemia or other tick-borne diseases to a veterinarian promptly, especially after engaging in an outdoor activity or after finding ticks on them.
Report any unexplained large die-off of animals, especially rodents or rabbits, to your local animal control agency or IDNR biologist.

References and Resources
1) Tularemia in Animals. Merck Veterinary Manual. Available online.
2) Tularemia. IDPH. available online.
3) Ehrensperger, F., Riederer, L. and Friedl, A., 2018. Tularemia in a jogger woman after the attack by a common buzzard (Buteo buteo): a” one health” case report. Schweizer Archiv fur Tierheilkunde, 160(3), pp.185-188.
4) Rabbit Fever on the Rise in Central Illinois
5) Deaths Reported in Several Area Squirrels, Tularemia Identified. Champaign-Urbana Public Health District. Available online.
6) Sharma, R., Patil, R.D., Singh, B., Chakraborty, S., Chandran, D., Dhama, K., Gopinath, D., Jairath, G., Rialch, A., Mal, G. and Singh, P., 2023. Tularemia–a re-emerging disease with growing concern. Veterinary Quarterly, 43(1), pp.1-16.

Dr. Nelda Rivera's research focuses on the ecology and evolution of new and re-emerging infectious diseases and the epidemiology of infectious diseases, disease surveillance, and reservoir hosts’ determination. She is a member of the Wildlife Veterinary Epidemiology Laboratory and the Novakofski & Mateus Chronic Wasting Disease Collaborative Labs. She earned her M.S. at the University of Illinois at Urbana-Champaign and D.V.M at the University of Panamá, Republic of Panamá.

Dr. Nohra Mateus-Pinilla is a veterinary Epidemiologist working in wildlife diseases, conservation, and zoonoses. She studies Chronic Wasting Disease (CWD) transmission and control strategies to protect the free-ranging deer herd’s health. Dr. Mateus works at the Illinois Natural History Survey- University of Illinois. She earned her M.S. and Ph.D. from the University of Illinois Urbana-Champaign.