Hospitals across Long Island are reporting a troubling rise in tick-borne illnesses this summer, prompting officials to renew warnings about tick exposure and prevention.

Over the past three years, New York state has seen an average of more than 17,000 new Lyme disease cases annually. Experts say the numbers could grow even higher this year, as ticks are appearing in greater numbers and in new locations not previously considered high-risk.

“It’s been a very active season for the ticks,” said Dr. Andrew Handel, of Stony Brook Medicine. “It seems to be summers and springs and shorter winters allow the ticks to really thrive and find more people to bite throughout the year.”

Dr. Handel also noted that rising deer populations may be contributing to the spread of ticks, which use deer as one of their primary hosts.

To protect yourself from tick bites, health officials recommend wearing light-colored long pants and long-sleeved shirts when spending time outdoors, especially in wooded or grassy areas. Closed-toed shoes are also advised.

In addition, using an insect repellent that contains DEET can help deter ticks. Experts also stress the importance of thoroughly checking for ticks after spending time outside, especially in hard-to-see areas like the scalp, behind the ears, and around the waist.