All four of us have it....my six year old brought it home from school and gave it to the rest of us. (I personally think he took that lesson in sharing in a little too seriously.) The pediatrician told me that it mimics the flu but the flu test shows negative. All four of us have has some of the same symptoms, but yet, have had different symptoms as well. And you're right about the relapse. My kids went 24 hours without fever....I tho't "whew" it's over....wrong. I went back to work and my mom called me to say they had had a fever spike. This is some nasty "stuff".