Dot Elmore, age 12, of Manchester, N.H., for her question:

HOW DOES A PERSON GET BRONCHITIS?

Bronchitis is the inflammation of the bronchial tubes leading to the lungs. Doctors tell us that lung infections, heart disease and hay fever may be some of the reasons for chronic bronchitis.

Chronic bronchitis is a continued inflammation of the bronchial tubes. Reports show that excessive smoking is also an important cause of chronic bronchitis.

Acute bronchitis results from an infection. A common cold may extend from the nose to the bronchial tubes and cause bronchitis. Bronchitis may also extend to the lung substance, causing some form of pneumonia.

A patient who has acute bronchitis with fever should remain in bed and preferably under a doctor's care. Asthma and bronchitis areclosely related, and one disease may cause the other.