Holland America is working hard to prevent its passengers from spreading communicable stomach viruses.  In every common area and when embarking the ship, there is a Purell hand sanitizer dispenser or a crew member to dispense hand sanitizer.  In addition, for the first 48 hours of the cruise, self-service at the buffet is suspended.  There is still food (thank goodness), but a member of the crew has to serve it to you.