Without proper cleaning and sanitation, playground equipment can quickly become a breeding ground for a host of bacteria, germs and viruses that can potentially cause health issues for children. Norovirus, E. coli, salmonella, and hepatitis A are just a few of the common bacterium and illnesses that can be found in children's playgrounds. In addition, already sick children can present even more of a health threat to other children. Infection can occur with a simple, accidental bump into a contagious playmate or the light touch of a contaminated surface where they can remain active for days.

https://www.aaastateofplay.com/guide-to-playground-hygiene/