YORK, Pa. (WHTM) – Pennsylvania will once again lead the nation in reported cases of Lyme disease this year.

Preliminary data from the Centers for Disease Control and Prevention shows the state had 12,092 cases of the tick-borne disease through Dec. 24.

“Temperature-wise, it’s right, geography is right, and the difficulty is not always knowing that you have been bitten by that tick,” said Matthew Howie, the medical director of the York City Bureau of Health.

The number is three times higher than cases reported in New York, second-highest in the nation with 4,002 this year, and New Jersey which has 3,850 infections for the third-highest total.

There were about 9,000 cases in Pennsylvania last year.

“We also have a lot of trees, a lot of deer, and a lot of ticks that go with the deer,” Howie said, “so it’s kind of a crossroads of all of those factors that kind of need to be connected.”

Symptoms of Lyme disease include fever, chills, joint aches, swollen lymph nodes, headache and rashes. If left untreated, the disease can lead to arthritis and other problems.

“We’re in the winter months, we don’t think about ticks. Warm weather breaks, the ticks can re-emerge. Every once in a while, people will talk about finding ticks during the winter months, but really this is a spring, summer, and fall where we see the largest number of infections get diagnosed,” Howie said.

The Pennsylvania Department of Health has cautioned that the 2016 figures haven’t been finalized yet.The Associated Press contributed to this report.Get breaking news, weather and traffic on the go. Download our News App and our Weather App for your phone and tablet.