A potentially deadly virus commonly found on cruise ships infects 20 million Americans on land a year, according to data from the Centers for Disease Control and Prevention.

The data, released Tuesday, shows that the norovirus infects more people on land than on cruise ships like commonly believed, Businessweek reported. Each year the virus affects nearly one in 15 Americans on land and ships combined, while the virus is responsible for just one percent of cruise ship sicknesses.

Various norovirus outbreaks have occurred on cruise ships over the past few years, including one in January that sickened 600 passengers and crew members aboard a Royal Caribbean ship.

Bur the CDC warns that the sickness can just as easily be contracted on land. The data showed that contaminated food plays a factor in spreading the virus because of the large number of people that may eat from the same source, Businessweek reported.

"The food service industry has a crucial role to play in preventing norovirus outbreaks in contaminated food," CDC Director Tom Frieden told Businessweek.  

The norovirus, for instance, can easily spread if restaurant employees touch infected surfaces in kitchens and do not wash their hands.

"One in five food workers in restaurants report having worked while ill with vomiting or diarrhea for at least one shift in the previous year," according to the CDC, Businessweek reported. But low wages and unpaid sick leave prevent some workers from taking time off to recover at home.            

The norovirus is also hard to get rid of. It can live on surfaces for days, survive in freezing and boiling-hot temperatures and is resistant to the most common disinfectants.

To prevent more infections, the CDC recommends kitchens be monitored by managers who specialize in food safety. The center is also calling for laws that require paid sick leave and rules that make sure ill employees stay home, Businessweek reported.