Bronchiolitis, Viral

**Definition:** An acute inflammatory disease of the lower RESPIRATORY TRACT, caused by paramyxoviruses, occurring primarily in infants and young children; the viruses most commonly implicated are PARAINFLUENZA VIRUS TYPE 3; RESPIRATORY SYNCYTIAL VIRUS, HUMAN; and METAPNEUMOVIRUS.

**Tree numbers:** - C01.748.099.135.321 - C01.925.109 - C08.127.446.135.321 - C08.381.495.146.135.321 - C08.730.099.135.321