Question

what is the single most effective way to prevent the spread of disease

Answer 1

If you're talking about sexually transmitted diseases, then it would be abstinence.

Answer 2

handwashing!

Answer 3

http://connect.ons.org/ons-connect-blog/prevent-the-spread-of-disease-and-illness

"Nurses most certainly should know this answer—hand washing, hand washing, hand washing! Although all of the above interventions can help prevent the spread of illnesses, hand washing is the single most important way to avoid getting sick and spreading germs to others."

Answer 4

staying sanitary