It’s the stuff nightmares are made of: dreams crushed, money wasted…oh, and five days stuck in an enclosed space awash with vomit. That’s pretty much how passengers of the Royal Caribbean’s Explorer of the Seas describe the cruise that was cut short at the end of January after what authorities believe was an outbreak of the norovirus onboard. There were at least 600 diagnosed cases of the outbreak but possibly 1,000 passengers and staff were exposed to this highly contagious bug. CNN even reports that this voyage set a record for the most reported cases of illness on a cruise ship in two decades. According to National Geographic, outbreaks like these aren’t necessarily on the rise, but are more likely in situations where there is close contact and shared food. Cruises provide an ideal environment for the spread of infection—but so do schools, stadiums, and emergency shelters. The CDC has a page dedicated to cruise ship travel safety that offers smart disease prevention tips to follow under any circumstances. As ever, the basics are crucial: hand washing , clean water, and properly cooked food ) will go a long way toward keeping everyone healthy.