11/21/2002 - Updated 04:18 PM ET

Despite illness, ships don't harbor more germs

By Gene Sloan, USA TODAY

Worried about all the reports of flu-like illnesses on cruise ships this year?

Relax, scientists at the Centers for Disease Control and Prevention in Atlanta say. The risk of catching something on a vacation at sea isn't going up. If anything, it's going down.

"We've seen a decline in the relative number of gastroenteritis outbreaks since 1990," says Elaine Cramer, a CDC epidemiologist who has studied the issue. "It just looks like there are more outbreaks, because there are more ships and passengers at sea."

Cramer is heading up the CDC's investigation of the latest outbreak of flu-like illness at sea, which occurred this month aboard Holland America's Amsterdam. More than 400 passengers on four successive cruises came down with the Norwalk virus, one of the most common types of gastrointestinal illnesses. Like influenza, it causes nausea, vomiting and diarrhea. It lasts one to three days.