Pandemic On The Brink Expansion 2013 Edition

Has saving humanity become routine? Spice  Pandemic  up with new roles and events. Add a fifth player, try Legendary difficulty, or add an optional challenge:  
€¢ What if one disease is particularly nasty?  
€¢ Or, if a fifth disease is wreaking havoc?  
€¢ Or, even worse, if that fifth disease is being spread by a hidden Bio-Terrorist?