What causes croup?

Croup is usually caused by viruses. It is most often caused by the parainfluenza virus, but it can also be caused by several other viruses including the flu viruses (influenza A and B). Bacteria sometimes also cause croup.

The flu virus and other types of virus can spread when someone who is infected sneezes or coughs, releasing droplets that contain the virus into the air. These droplets can be breathed in by others or transferred to anyone who may touch a surface contaminated with droplets containing the virus, leading to infection.

Croup, and other respiratory tract infections, can be prevented by washing hands often with soap and water, particularly when in you or your child come in contact with someone who has the illness. Read more about how to prevent croup.

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  • NHS Choices – croup: www.nhs.uk/Conditions/Croup/Pages/Causes.aspx (accessed 18 April 2012)