Hantavirus isn’t the only thing that’s been making people sick on boats lately. There’s now a relatively large outbreak of norovirus aboard a Princess Cruises ship. Over a hundred people on the Caribbean Princess  have come down with norovirus, according to the Centers for Disease Control and Prevention. The ship is on a two-week voyage and has docked today in Florida. It’s the fourth such cruise-related outbreak of gastrointestinal illness reported this year. Cruise outbreak Norovirus is the world’s leading reported cause of foodborne outbreaks, one that typically causes several days’ worth of diarrhea and vomiting. In the U.S., it sickens roughly 20 million people a year, while sending 100,000 people to the hospital annually. Though norovirus can be caught everywhere, the cramped environments and widely shared meals found on cruise ships can make them a source of large-scale outbreaks. The CDC was notified about this latest outbreak late last week.…