Dear Doctor: We moved from the city to rural Massachusetts, and suddenly Lyme disease is a real threat. I’ve read about it forever, but now that we’re here, I realize I don’t know much about the disease. How do you know if you’ve got it? And how do we protect ourselves and our kids? Dear Reader: Lyme disease is one of a range of illnesses that can occur when an individual is bitten by a tick. In t…