Aug. 3 (UPI) — Three confirmed cases of tularemia, also known as rabbit fever, have been reported in New York this year, health officials said Monday.

The cases are located in Suffolk County, N.Y. The disease causes symptoms that doctors warn can be more severe than Lyme disease.

Like Lyme disease, rabbit fever is spread through tick bites. Its symptoms include high fever, extreme fatigue, chills, headaches, swollen lymph nodes and gastrointestinal issues.

Earlier this year, 9-year-old John Detmer was diagnosed with tularemia after suffering a tick bite on his head. His symptoms lasted several weeks.

Detmer was diagnosed after being sent to an infectious disease doctor.

Along with a direct bite from a tick, the disease can be spread through contact with an infected animal. Rabbits are among the most common carriers of tularemia, hence the name rabbit fever. Rodents and biting insects may also transmit the disease.

Tularemia is caused by a bacterial infection. It is a rare illness and one of the first indicators is a tick bite that develops into an open wound.

“Confirmation of a tularemia diagnosis requires a combination of laboratory testing and fulfillment of specific clinical or epidemiologic criteria,” the Suffolk County Department of Health said. “The laboratory testing to confirm a tularemia diagnosis may take several weeks.”