Term for any person with a communicable disease/virus that willingly goes out in public, hangs with friends and spreads their sickness to the people around them.
Origins of the term come from the movie "Outbreak"
Bob knew he had the flu when he decided to go to the bar. He's such a dirty plague monkey.

by Nixodemus April 14, 2007
An employee who still comes in to work sick and spreads his germs all over the place when he should stay home.
Bob came in to work sicker than a plague monkey just to get his work done. Now everybody is going to get sick.
by Roy Mulders May 6, 2007