parainfluenza virus /per′ə·in′flo̅o̅·en″zə/ [Gk, para + It, influenza, influence] , a myxovirus with four serotypes, causing respiratory infections in infants, young children, and, less commonly, adults. Type 1 and 2 parainfluenza viruses may cause laryngotracheobronchitis or croup; type 3 is a cause of croup, tracheobronchitis, bronchiolitis, and bronchopneumonia in children; and types 1, 3, and 4 are associated with pharyngitis and the common cold. Compare influenza, rhinovirus.
