Bronchiolitis is an inflammation of the small air passages (bronchioles), usually caused by a virus (respiratory syncytial virus, or RSV, is one such virus).
Bronchiolitis usually affects children under the age of 2 years. It is the leading cause of serious lower respiratory illness in infants.
Symptoms of bronchiolitis include labored, rapid breathing with wheezing and a cough that sounds "tight." If the infection becomes severe, the infant's breathing rate may increase noticeably.
If severe difficulty breathing occurs, immediate medical attention is needed.
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