<unk>  usually affects children under the age of 2 years, with a peak age of 3 - 6 months.<unk>  is a common disease in children and sometimes causes severe illness. Respiratory syncytial virus (RSV) is the most common cause of<unk> . Other viruses that may cause<unk>  include adenovirus, influenza virus and parainfluenza virus. It may be caused by bacterial organisms like Legionella pneumophilia and Mycoplasma pneumonia. Other noninfectious causes include smoking, collagen vascular disease. It may also be caused after bone marrow transplant.
Bronchiolitis causes
Bronchitis causes
Bronchiectasis causes
Pneumoconiosis causes
Tracheitis causes
Airway obstruction causes
Aspiration pneumonia causes
Occupational lung disease causes