title: Influenza A 2  virus as a cause of croup requiring tracheotomy.
mesh_terms: D000402:Airway Obstruction / Q000601:surgery; D000906:Antibodies / Q000032:analysis; D002675:Child, Preschool; D003168:Complement Fixation Tests; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D007251:Influenza, Human / Q000276:immunology / Q000601:surgery; D007827:Laryngitis / Q000382:microbiology / Q000601:surgery*; D009975:Orthomyxoviridae; D014140:Tracheotomy
chemical_list: D000906:Antibodies