RSV is a virus that is a major cause of bronchiolitis and pneumonia during infancy and early childhood.

It induces formation of large syncytial masses in cell cultures, and this led to its being so named.

When a child under two years of age presents in midwinter with a runny nose, dry cough, and mild to moderate fever, chances are that he or she has respiratory syncytial virus infection (RSV).

Although the illness usually runs its course in two to three weeks, infection can be life-threatening in...