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About Parainfluenza (Croup)

The human parainfluenza viruses (HPIVs) are a group of viruses that cause upper and lower lung infections. Parainfluenza viruses are a common cause of cold symptoms. It is also the major cause of croup in children.   

Croup is a sudden swelling of the upper airway that is caused by parainfluenza virus type 1 infection. Most symptom of croup is a bark-like cough or high-pitched sound when breathing in (inspiratory stridor), often occurring at night. This is a sign that the airway is partially blocked. Once infected with the virus it can take 2 to 7 days for symptoms to show. This virus most commonly arises in the spring, summer, and fall.