What's the difference between Infectious and Contagious?

"Infectious" means capable of causing an infection, usually by a pathologic microorganism. "Contagious" means that the the disease is transmissible by direct and indirect contact. This site has a table that shows examples of contagious and not contagious bacterial infections and contagious and not contagious viral infections. All the microorganisms causing those infections are infectious.

Ah, thanks Kalleh . I knew there must be a difference, but I've never been quite sure what it is.