My 14 year old dd had a mystery illness where her temperature went up and down for three days. She then took about four weeks to recover properly.
She was the only one in the house ill though we all felt a bit laid low.
We then saw our dentist who asked how we all were. When we told her about it she said she had lost count of the number of children her age who had suffered similar.
The only conclusion I can come to is that there was something going around that this age group were not immune to. So I am interested if others have noticed similar.