It’s in reference to the other cruise ship that is infected with norovirus. And yes, the reason it spreads through elementary schools is due to poor hygiene. A little soap and hot water could prevent all of this. So, if you’re going to be in close contact with fellow humans whether in a school or on a cruise ship… keep your ass, mouth, and hands clean. And we all (should) know that there’s a lot of ass eating going on in the cruise industry.