The scourge that"s plaguing cruise lines—and causing thousands of tourists to rethink their holiday travel plans—didn"t start this year, nor did it even start on a ship. It began, as far as the Centers for Disease Control(CDC) can tell, in Norwalk, U.S., in October 1968, when 116 elementary school children and teachers suddenly became iii. The CDC investigated, and the cause was discovered to be a small, spherical, previously unclassified virus that scientists named, appropriately enough, the Norwalk virus.Flash forward 34 years, and Norwalk-like viruses (there"s a whole family of them) are all over the news as one ocean liner after another limps into port with passengers complaining of nausea and vomiting. The CDC, which gets called in whenever more than 2% of a vessel"s passengers come down with the same disease, identified Norwalk as the infectious agent and oversaw thorough ship cleaning—which, to the dismay of the owners of the cruise lines, haven"t made the problem go away.So are we in the middle of an oceangoing epidemic？ Not according to Dave Forney, chief of the CDC"s vessel-sanitation program. He sees this kind of thing all the time; a similar outbreak on sever al ships in Alaska last year got almost no press. In fact, he says, as far as gastrointestinal illness goes, fewer people may be getting sick this year than last.Norwalk-like viruses, it turns out, are extremely common—perhaps second only to cold viruses-and they tend to break out whenever people congregate in close quarters for more than two or three days. Oceangoing pleasure ships provide excellent breeding grounds, but so do schools, hotels, camps, nursing homes and hospitals. "Whenever we look for this virus," says Dr. Marc Widdowson, a CDC epidemiologist, "we find it." Just last week 100 students (of 500) at the Varsity Acres Elementary School in Calgary, Canada, stayed home sick. School trick？ Hardly. The Norwalk virus had struck again.If ocean cruises are your idea of fun, don"t despair. This might even be a great time to go shipping for a bargain. The ships have been cleaned. The food and water have been examined and found virus free. According to the CDC, it was probably the passengers who brought the virus aboard.Of course, if you are ill or recovering from a stomach bug, you might do everybody a favor and put off your travel until the infectious period has passed (it can take a couple of weeks). To reduce your chances of getting sick, the best thing to do is wash your hands—frequently and thoroughly—and keep them out of" your mouth.One more thing: if, like me, you are prone to motion sickness, don"t forget to pack your Drama mine.According to the passage, CDC is an organization that
A．works against the Norwalk-like viruses.B．helps to control diseases.C．specialized in treat virus in ocean liners.D．works for the benefits of cruise owners.