Global Disease

With a Global Disease, it's really possible for Exactly 8.3 Million people to come down with it at some point.

The contagious illness that's either spread around the world or another large area such as a continent or has already spread widely. When a Global Disease strikes, it's time for someone to find the Vital Cure to Save The World from global death. As they're going on their journey to Save The World, they may meet people who are being infected by the Global Disease. Bonus Points if somebody pulls a Not Really Okay on us on this search for the Vital Cure.