Delphine Willis, age 9, of Florence, S.C., for her question:

HOW DO CHILDREN GET RHEUMATIC FEVER?

Rheumatic fever is a serious disease that occurs in children and young adults. It has been estimated that about 250,000 people contract it each year.

Rheumatic fever, doctors believe, is caused by streptococci similar to the one that causes a sore throat. But no one knows exactly how the attack can cause rheumatic fever.

The disease starts with mild pains in the muscles which become intense. The person's joints then swell. Rheumatic fever is also one of the greatest causes of heart diseases in young people.

A person with rheumatic fever will be given complete rest in bed by the doctor. Drugs of the salicylate group, including aspirin, are given to ease the pain and Cortisone is often also prescribed in the treatment.