(University Park) -- As warmer weather arrives in Pennsylvania, so will deer ticks -- insects which can carry Lyme disease. Penn State extension entomologist Steve Jacobs says the disease can cause a variety of symptoms, including chills, swollen lymph nodes and fatigue. "Probably the worst thing that occurs with it is the arthritic condition if left untreated," he says. "Also there can be neurological complications, some paralysis possibly, temporary, numbing of the extremities and various things." Jacobs says deer ticks are much more common than they used to be in the state, and tick populations are highest between May and July. Adams and York counties tend to have the highest number of cases of Lyme disease in the midstate each year. It takes up to 48 hours for a tick to transmit the disease, so Jacobs recommends using tweezers to quickly remove the pest once its found. He says people should be sure to cover up if they go into brushy areas and should use insect repellent with the ingredient DEET.