A tick bites you on a trail in McLean or a golf course in Middleburg, and you barely notice. Six weeks later you are waking at 2 a.m. with hives, stomach cramps, or a racing heart, a few hours after dinner and for no reason anyone can explain. Every test your doctor runs comes back normal. You are told it is IBS, perimenopause, or stress, or handed the word idiopathic, which in plain terms means no one knows.