There are so many childhood diseases , infectious and non-infectious, bronchitis is most often caused by a viral infection. It may also be caused by bacteria or things such as dust, allergens, strong fumes, or tobacco smoke. In children, the most common cause of acute bronchitis is a virus. The illness may develop after a cold or other viral infection in the nose, mouth, or throat Such illnesses can spread easily from direct contact with a person who is sick. A number of different viruses cause bronchiolitis which affects children less than one year of age. Most commonly, it is caused by respiratory syncytial virus, but it can also be caused by influenza and other common viruses associated with upper respiratory symptoms such as fever, runny nose, and cough. A common symptom of bronchiolitis includes all of the above and wheezing the same symptom observed in children with asthma. It is common in the winter months, and some infants will require admission to a hospital wh...