elizabeth cohen joining us. here we go. norovirus, sick, sick, sick. >> so not fun. so not fun. >> what does it do? >> two words, vomiting and diarrhea. i'm sorry to be so blunt, but that's what it is. and you feel -- it is disgusting. you feel horrible. if you're generally a healthy person, it lasts a couple of days and you're fine. if you're very old or if you're very young or if you have any immune problems, it can be much more complicated. >> do we know how it starts? >> it spreads around. it is a bug that spreads around, person to person. if you were sick and touched this table and then i touched this table, i could get the bug that way. this bug is so contagious, if you have it, chances are your family is going to get it too. >> we heard about this before on cruise ships. so is this common? >> i would say it is not uncommon. >> not uncommon. >> not uncommon at all. it is so not uncommon that the cdc has very strict guidelines for sanitizing these ships. they are supposed to be really rigorous about sanitizing them,