sentence: Most croup is caused by a virus infection.
sentences_after: Some people call severe laryngotracheitis croup. This disease is caused by a milder virus. Croup also can be laryngeal diphtheria, bacterial tracheitis, laryngotracheobronchitis, and laryngotracheobronchopneumonitis. These diseases are caused by bacteria and are more severe.
concept_name: croup
headings: Croup Causes
categories: Viruses Respiratory system Infectious diseases