Cruise ships are required to report these outbreaks, the CDC said. The Rotterdam, a Holland America Line cruise ship, reported theirs on Feb. 7. This is the fourth outbreak reported to the agency this year.

A norovirus outbreak on a nearly two-week-long Holland America cruise ship sickened 152 passengers and more than a dozen crew members with symptoms like vomiting and diarrhea, health officials said. Just under 6% of the 2,