Lucy Notarantonio is Newsweek's Senior Lifestyle and Trends Reporter, based in Birmingham, UK. Her focus is trending stories and human interest features ranging from health, pets and travel.

A narrowing of the smallest airways in the lung (bronchioles) causes wheezing. This narrowing results from swelling caused by a virus. The respiratory syncytial virus (RSV) causes most bronchiolitis.

A narrowing of the smallest airways in the lung (bronchioles) causes wheezing. This narrowing results from swelling caused by a virus. The respiratory syncytial virus (RSV) causes most bronchiolitis.