Health officials on Long Island are warning residents after three probable cases of tularemia, also known as rabbit fever, were confirmed by the Suffolk County Department of Health Services.

The illness is rare but can be serious, and the local alert comes as officials point to tick exposure as a possible route of infection in at least one reported case near a major metro area.

"SCDHS currently has three probable cases of tularemia this year," the agency said in a statement provided to local outlets. "Confirmation of a tularemia diagnosis requires a combination of laboratory testing and fulfillment of specific clinical or epidemiologic criteria. The laboratory testing to confirm a tularemia diagnosis may take several weeks."

One case involved a 9 year old patient who was bitten by a tick while playing outside, according to NBC4 New York.

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After the tick was removed, he later developed high fever, severe head and neck pain, swollen lymph nodes and glands, body aches and extreme fatigue.

The boy remained ill for nearly a month and had multiple doctor visits before an infectious disease specialist diagnosed him with tularemia.

Although wild rabbits live in the family yard, the patient’s mother said he never handled the animals.

Doctors believe infected ticks likely fed on the rabbits before biting the boy and transmitting the bacteria, according to reports.

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Tularemia is caused by the bacteria Francisella tularensis and commonly infects rabbits, hares and rodents.

The disease is zoonotic, meaning it can spread from animals to humans.

The bacteria is classified as a tier 1 select agent, a designation for agents and toxins that the CDC says present the greatest risk of deliberate misuse with significant potential for mass casualties or devastating effects to the economy, critical infrastructure or public confidence, and pose a severe threat to public health and safety.

Although tularemia remains rare, 196 cases were reported in the United States in 2023.

CDC surveillance found 2,462 cases between 2011 and 2022, marking a 56% increase in incidence compared with the previous decade, from 2001 to 2010.

Daniel Ruderfer, M.D., chief of the Division of Pediatric Infectious Diseases at Hackensack Meridian K. Hovnanian Children's Hospital in New Jersey, previously told Fox News Digital that the increase in reported cases is likely tied mostly to improved microbiology detection methods.

"The traditional method of confirming cases has historically been via growth in culture and antibody testing," he said.

"However, newer detection methods, such as PCR testing , are likely a major contributor to the increase in reported cases."

Humans can contract tularemia through bites from deer flies or ticks, contact with infected animals, or exposure to contaminated water or aerosols, according to the same source.

Symptoms can vary depending on the type of disease.

Ruderfer said general symptoms include chills, headache, malaise, fatigue, anorexia, myalgia, chest discomfort, cough, severe sore throat, vomiting, diarrhea and abdominal pain.

"Depending on the location of the infected bit or scratch, people can develop localized lymphadenopathy (enlarged lymph nodes) and a cutaneous ulcer at the infection site," he said.

"Other manifestations include conjunctivitis, pneumonia and potentially even bloodstream infections."

The death rate from tularemia is typically low, at less than 2%, although the CDC noted that it can be as high as 24% in rare, severe cases.

The illness can be treated with antibiotics, but no vaccine is currently available.

People most at risk include children between 5 and 9 years of age, older men, American Indian and Alaskan Native people, and those living in central U.S. states, according to the report.

Ruderfer noted that the general population is not at an obvious risk for infection unless people come into physical contact with an infected rabbit, tick or deer fly.

He advised that people who hunt or routinely interact with rabbits should see a doctor if they develop concerning symptoms.

The CDC wrote that many factors might contribute to the higher risk among American Indian and Alaskan Native people, including the concentration of Native American reservations in central states and activities that might increase contact with infected wildlife or arthropods.