What is Contagious ?
Contagious is (adj) 1. (of a disease) which can be spread to other people by touching an infected person or objects which an infected person has touched Did you have any contagious diseases when you were a child? Your child is no longer contagious and can go back to school. Compare infectious 2. which can be passed on to someone else He’s a great music teacher and his enthusiasm for music is very contagious.
source: Easier English, Student Dictionary Upper Intermediate Level