Probable Rabbit Fever Cases Raise Concerns About This Rare Tick-Borne Disease

Warmer temperatures and milder winters continue to raise the risk of life-threatening tick-borne illnesses for people in the United States.

While Lyme disease is the most common such infection in North America, a rare tick-transmitted illness called tularemia (nicknamed “rabbit fever”) made headlines this week as three probable cases were detected in Suffolk County, New York.

Tularemia is caused by the bacterium Francisella tularensis. The bacterium naturally occurs in small rodents and other wild animals, which then gets picked up by the ticks and insects that feed on them. People most commonly get sick from tick bites or contact with sick animals. It doesn’t spread from person to person.

“It’s called rabbit fever because rabbits are the primary carrier, but this is an unusual infection in any mammal, including humans,” says Sharon Nachman, MD, the division chief of pediatric infectious disease at Stony Brook Medicine in Suffolk County, New York. “There are only about 200 reported human cases in the U.S. annually. This is just not a very transmissible disease, so we still don’t expect to see a big rise in cases this year.”

The New York State Department of Health has yet to officially confirm the three probable cases, according to state health department spokesperson Marissa Crary.

Why Is Rabbit Fever Getting Attention?

Cases of tick-borne illness have been mounting in recent years, raising concerns that they pose a growing public health threat. Just this spring, data from the Centers for Disease Control and Prevention (CDC) showed that weekly emergency room visits for tick bites were at their highest level since 2017.

For tularemia in particular, overall case numbers remain low, but another 2025 CDC study found that the average rabbit fever cases surged by more than 50 percent between 2011 and 2022. Rates were highest among children ages 5 to 9, older men, and American Indian or Alaska Natives.

“The fact is tularemia and other tick-borne diseases are showing up in more places and being recognized more often,” says Peter Chin-Hong, MD, an infectious disease specialist and a professor of medicine at the University of California San Francisco School of Medicine.

Dr. Chin-Hong believes that climate change is contributing, as warmer winters and longer summers increase the number of months that ticks are active and people are outdoors. Warmer conditions may also support larger animal populations to feed these ticks. Additionally, building and construction have been pushing deeper into natural environments, making exposure more likely.

Public health authorities may be especially alarmed by possible tularemia cases because the bacterium that causes the illness, Francisella tularensis, is a Tier 1 bioterrorism threat. F. tularensis has been explored as a bioterrorism agent because it can cause incapacitating, potentially fatal illness.

Symptoms of Rabbit Fever (Tularemia)

Rabbit fever can be tricky to identify because its symptoms can mimic those of many other infections, especially early on.

“This is why the diagnosis is often missed at first,” says Chin-Hong.

Early signs and symptoms can resemble the flu and include:

Fatigue
Headache
Fever and chills
Muscle pain and aches (myalgia)
Chest discomfort or cough
Sore throat
Loss of appetite
Vomiting and diarrhea
Abdominal pain
Swollen lymph nodes
Severe eye irritation if bacteria enters eye

Dr. Nachman notes that with tularemia, an ulcer (an open, painful sore) can form at the site of the tick bite, and swollen, tender, hot lymph nodes may develop in that area.

Ultimately, the only definitive way to confirm rabbit fever is through lab testing. When caught early, rabbit fever can be effectively treated with antibiotics such as doxycycline, streptomycin, gentamicin, and azithromycin.

Without prompt treatment, however, tularemia can be fatal in 10 to 50 percent of cases.

Recognizing Possible Exposure

A fast, accurate diagnosis of rabbit fever can be made if a person has been in a situation or environment where contact with the bacteria is more likely, for example, time spent outdoors or around sick rabbits.

“We advise families to stay away from rabbits that are not behaving in a normal fashion,” says Nachman. “People may think, ‘Aww, there’s a cute bunny and I want to help it,’ but a sick animal is a sick animal, so don’t approach it or you may get an infection.”

But direct contact with a tick is the most likely way for a human to become infected. Ticks can feed for hours at a time, increasing the chances that a pathogen will spread from the tick to the human, says Chin-Hong. “Ticks also inject saliva continuously during feeding, which may suppress the immune system locally and increase the chances of infection,” he says.

Protecting Yourself From Tick Bites and Rabbit Fever

If you’re spending time outdoors in areas where ticks and infected rabbits may thrive, Chin-Hong suggests following tick prevention tips.

Wear long sleeves and pants outdoors. Tuck pants into socks and wear light-colored clothing so ticks are easier to see.
Use insect repellents. DEET and picardin products are effective against ticks.
Apply permethrin to clothing only. This powerful insecticide should never be applied directly on skin.
Check yourself for ticks. After time outdoors, thoroughly scan your body, and your kids and pets, for ticks.
Wear gloves when handling sick or deceased animals. Better yet, don’t touch them.
Check areas carefully before lawn mowing. Mowing over a dead infected animal can aerosolize the bacteria.

If you do find a tick on your body, don’t panic. Chin-Hong recommends:

Remove it as soon as possible. Use fine-tipped tweezers, grasping the tick as close to the skin as possible then pulling it straight out. Don’t twist the tick as you remove it. It’s not necessary to save the tick.
Clean the bite area and your hands. Use soap and water or rubbing alcohol.
Watch for tick symptoms. You don’t need to immediately see a doctor, but carefully watch for signs of illness. If flu-like symptoms appear, see a healthcare provider as soon as possible.