Nearly 100 people got sick in a norovirus outbreak on a Holland America Line cruise, the second on its ships this month. Among 2,192 guests on its Rotterdam ship, 83 reported being ill during a voyage that ended Friday,

There are about 2,500 reported norovirus outbreaks in the U.S. each year. Norovirus, which is sometimes called the "cruise ship virus," causes more than 90% of diarrheal disease outbreaks on cruise ships, according to the CDC. However, norovirus outbreaks on cruise ships account for only a small percentage of all reported norovirus outbreaks.