Dr. John Aucott loves to let his dog go off-trail when he hikes. But as the director of the Johns Hopkins Rheumatology Lyme Disease Research Center in Baltimore, he knows better than to do it in June and July the height of Lyme Disease season, when tiny nymph-stage ticks can move, undetected, from wild host (a mouse or deer) to a dog or human. While dogs cant directly transmit Lyme disease to their owners, they can harbor ticks capable of doing the job .

People who get Lyme disease suffer from unpleasant symptoms like a rash, facial paralysis and swollen knees. But it isnt always easy to detect and if left untreated, can progress to complications like memory problems, heart rhythm irregularities and chronic arthritis. A small minority of people with Lyme disease may even suffer symptoms like fatigue and joint pain for months after treatment.

This year, because of the East Coasts unusually warm winter, ticks seem to be making an earlier appearance, which could make people unknowingly vulnerable to getting Lyme disease. Aucott says he is already finding ticks on his dog.

I just pulled an engorged tick off [the dog] in February, which would be very unusual if the ground was snow-covered and it was 30 degrees, he said. But theres no snow, and its been 60 and 70 degrees for some reason this winter.