What diseases can you get from drinking off someone else?

Question

Serious answers please :)

Answer 1

Many illness can  be catched over by drinking on someone cup, I usually dont do it,  this is a very stupid traditioin specially in our spanish commuinity  ''''Im spanish''''

Ignorance is the main cause of this custom,  on the saliva of anyone are thousands if not millions of germens, bacterias, and a lot of microorganism ready to infect the first idiot who get in contact with.

Answer 2

Mononucleosis is the main one but a common cold and sore throat are up there too.