Americans return to the U.S. following hantavirus and norovirus exposure. Both infections spread aboard cruise ships.

Norovirus is a highly contagious virus that causes gastroenteritis, an inflammation of the stomach and intestines. It spreads primarily through contaminated food or water, surfaces, and close contact with infected individuals.

One the 17 American passengers evacuated from a cruise ship In the Canary Islands has tested positive for the hantavirus but is not showing any symptoms, U.S. health officials said late Sunday. The charter flight was carrying 17 Americans evacuated off the MV Hondius following its arrival in Tenerife,