Cruise ships are an environment unlike any other when it comes to the spread of disease. You have sometimes as many as 8,000 people from all over the world crammed into a boat together for a week or more. That means that each elevator button, handrail, tongs in the buffet, countertops are touched thousands of times each day. Unfortunately, not everyone is 100% healthy. While you can protect yourself from others, sometimes it is YOU who is the sick one. Here's what to do if you catch a cold while on a cruise ship.