Rabbit fever is the common name for tularemia, a bacterial infection caused by Francisella tularensis. It gets its nickname because rabbits are one of the most common animals to carry the bacterium, and hunters who handle infected rabbits are among the people most frequently diagnosed. The infection is uncommon but serious: the United States averages about 205 reported cases per year, with half of all cases concentrated in Arkansas, Kansas, Missouri, and Oklahoma.
How People Get Rabbit Fever
There are several distinct ways the bacterium enters the human body, and the route of exposure determines what type of illness you develop.
The most common route is through the skin. This happens when you handle infected animal tissue, particularly while hunting or skinning rabbits, muskrats, prairie dogs, or other rodents. Even a tiny cut or scratch can let the bacteria in. Domestic cats are also highly susceptible to tularemia and have transmitted it to their owners. There have even been outbreaks linked to pet-store hamsters, including at least one case where a child was infected by a hamster bite.
Tick and deer fly bites are another major source. In the U.S., the dog tick, wood tick, and lone star tick all transmit the bacterium. Deer flies have been linked to transmission in western states. You can also inhale the bacteria when mowing or doing landscaping work if machinery runs over an infected animal carcass, kicking contaminated dust into the air. Drinking untreated water that has been contaminated by infected animals is a less common but documented route.
Symptoms and Forms of the Disease
Symptoms typically appear within three to five days of exposure, though the incubation period can range from one to 21 days. What makes tularemia unusual is that it takes different clinical forms depending on how the bacteria entered your body.
The most recognizable form, called ulceroglandular tularemia, develops after bacteria enter through the skin. A painful ulcer forms at the site of infection, and nearby lymph nodes swell significantly. If the bacteria enter through the skin but no ulcer appears, it’s classified as glandular tularemia, with swollen lymph nodes as the primary sign.
If you touch your eyes after handling an infected animal, the bacteria can cause oculoglandular tularemia, which involves eye pain, redness, swelling, and discharge along with swollen lymph nodes near the ear. Drinking contaminated water can cause oropharyngeal tularemia, producing a severe sore throat, mouth ulcers, and swollen neck glands.
The two most dangerous forms are pneumonic and typhoidal tularemia. Pneumonic tularemia affects the lungs and develops after inhaling contaminated dust or aerosols. It causes cough, chest pain, and difficulty breathing. Typhoidal tularemia is the hardest to diagnose because it produces high fever, extreme fatigue, and sometimes organ involvement without a clear entry wound or swollen lymph nodes to point toward the cause.
How Rabbit Fever Is Diagnosed
Diagnosing tularemia can be tricky because early symptoms overlap with many other infections. The gold standard is growing the bacterium from a clinical sample, such as a swab from a skin ulcer, a lymph node biopsy, or blood. However, F. tularensis is slow-growing and requires special laboratory conditions, so doctors need to alert the lab when they suspect tularemia.
Blood tests that look for antibodies are commonly used, but there’s an important catch: antibodies often don’t show up until two to three weeks after symptoms begin. A negative blood test early in the illness doesn’t rule out tularemia. Doctors typically draw a second blood sample several weeks later to check for a rise in antibody levels. PCR testing, which detects the bacterium’s genetic material directly, can provide faster supportive evidence but is not considered confirmatory on its own.
Treatment and Recovery
Rabbit fever is treated with antibiotics, and the choice depends on how severe the infection is. For mild to moderate cases, oral antibiotics from the fluoroquinolone family are commonly prescribed for 10 days. Another option is a tetracycline-class antibiotic taken for 14 to 21 days, though this isn’t recommended as the sole treatment for severe infections or cases where treatment was delayed more than two weeks.
Severe infections are typically treated with an injectable antibiotic from the aminoglycoside class, sometimes combined with a second antibiotic for broader coverage. Doctors may extend treatment beyond the standard course if fevers persist or abscesses develop. With prompt antibiotic therapy, most people recover fully. Without treatment, tularemia can be life-threatening, particularly the pneumonic and typhoidal forms.
Why It’s Taken Seriously by Public Health Agencies
Despite its rarity, tularemia holds an outsized place in public health planning. F. tularensis is classified as a Tier 1 select agent by the U.S. government, the highest biosecurity category. The reasons come down to biology: the bacterium is extraordinarily infectious (inhaling as few as 10 organisms can cause disease), it can be aerosolized, and pneumonic tularemia has a high fatality rate if untreated. Federal guidelines include specific treatment protocols for scenarios involving intentional release, where dual antibiotic therapy is recommended from the start.
Reducing Your Risk
If you hunt, trap, or handle wild animals, wearing gloves is the single most important precaution. This applies especially when skinning rabbits, muskrats, and prairie dogs. Avoid handling any wild animal that appears sick or is found dead.
To prevent tick and deer fly bites, use EPA-registered insect repellents containing DEET, picaridin, IR3535, oil of lemon eucalyptus, or 2-undecanone. Wearing long sleeves and checking for ticks after spending time outdoors in endemic areas further reduces your exposure. If you’re doing yard work in rural areas, be aware that mowing over animal carcasses can aerosolize the bacteria, so removing dead animals before mowing is a practical step. When camping or hiking, avoid drinking untreated water from streams or ponds.