Merck Manual
North Bay Regional Health Centre
Children's Hospital of Eastern Ontario
Bronchiolitis
Bronchiolitis is an infection of the lungs caused by a virus that usually happens in the late fall and winter.
It causes the small breathing tubes in the lungs to become tight, swollen and filled with mucous. This can make it hard for air to move in and out of the lungs.
Bronchiolitis happens most often in children under one year of age and is the most common reason why babies are admitted to hospital.
The most common virus that causes bronchiolitis is Respiratory Syncytial Virus (RSV).
More Information about Bronchiolitis
Individual cases are not reportable to the Health Unit.
Should one go to childcare, school, or work if they have bronchiolitis?
Ill individuals should remain home until they do not have a fever, do not develop any new symptoms, and symptoms have been improving for at least 24 hours (48 hours for nausea, vomiting, and/or diarrhea).
Follow the direction of your healthcare provider or occupational health at your workplace.
Healthcare provider information
RSV immunization reduces the rate of hospitalization.
Clinical management and treatment will vary depending on the severity of symptoms. The diagnosis of bronchiolitis is based on clinical evaluation (e.g. patient history and physical exam) rather than diagnostic testing. Differential diagnoses must be excluded.
Refer to the following resources for additional information on assessment and management of bronchiolitis:
Choosing Wisely Canada
Canadian Paediatric Society
Merck Manual - Professional Version
Infection prevention and control
In healthcare settings, patients with bronchiolitis (regardless of specific viral etiology) should be cared for using droplet and contact precautions (including mask and eye protection for staff), optimally in a single room.
Contact our Communicable Disease Control (CDC) program at 705-474-1400 or toll free at 1-800-563-2808, ext. 5229, or by email to cdc@healthunit.ca for more information.
Last updated: Apr 2026, by CDC