I have a little brother, Brett, who is 6 years younger than me. Last year he started to get periodically sick with a fever every 3 weeks. He would stay sick for 3 or 4 days and then he would get better. My mom took him in to the doctor and she diagnosed him with some disease, I can’t remember its name, in which every 3 weeks his immune system goes haywire for 3 days and then gets better. This is not contagious, and there is no medication that can get rid of it. Apparently he will grow out of this disease when he goes through puberty. This means he will get sick 63 days of every year for a another 6 years.