Diseases come and go...
Storms come and go too! It rains for some time and then it stops. Few childhood illnesses approach like storms, as vomitings or pain in abdomen and even go like a storm.
Few are like rain, as cold or loose motions or fever and may last only a few days and go ..
Rest very few last like seasons as tuberculosis or a cyst in the brain .. They last for months.
Don't worry parents, your children improve with time and appropriate treatment.