Avoiding Serious Illness Afloat : Disease: The shigellosis outbreak aboard the Viking Serenade is being called ‘rare.’ But there are ways to cut your risks.

As more than 600 passengers and crew on the Los Angeles-based Viking Serenade discovered recently, walking up the gangway of a modern cruise ship doesn’t insulate its occupants from serious illness.

A 78-year-old man died and five other Viking Serenade passengers were hospitalized last month after a shipboard outbreak of shigellosis, an intestinal disease that strikes about 15,000 Americans a year.

Royal Caribbean Cruise Line’s 1,512-passenger Viking Serenade resumed its regular three- and four-day Mexico schedule after canceling two cruises when the shigellosis outbreak forced the ship to return a day early from its Aug. 29 sailing. More than a third of the ship’s passengers became sick, and at press time the source of the shigella flexneri bacteria was still under investigation.

In July, the spread of Legionnaires’ disease among passengers on Celebrity Cruises’ Horizon caused one death. Sixteen Horizon passengers contracted the respiratory disease, and another 34 cases are suspected.

Illnesses of such proportions are extremely unusual among the estimated 4.5 million travelers who take cruises from North American ports, according to the Atlanta-based U.S. Centers for Disease Control and Prevention. The Horizon is the only cruise ship that has been associated with an episode of Legionnaires’ disease, officials say. And the shigellosis on the Viking Serenade represents the largest of three gastrointestinal illness outbreaks the CDC has investigated on cruise ships this year, said CDC spokesman Tom O’Toole. The agency steps in whenever a cruise ship reports at least 3% of its passengers or crew with diarrhea or other symptoms of gastrointestinal illness.

“An outbreak (of gastrointestinal illness) on a cruise ship is a very rare event, period. And an outbreak of shigellosis is even rarer,” said O’Toole, who notes that the number of shipboard outbreaks has declined steadily, from an average of 12 to 15 per year in the 1970s to between one and four per year in the 1990s.

The Viking Serenade outbreak “is one of the largest we’ve ever seen,” O’Toole said. “It’s incredible to have an attack rate of 37%.” Most gastrointestinal illnesses the CDC investigates involve less than 10% of a ship’s passengers. “In a lot of cases, passengers become ill during shore excursions, not on the ship itself,” he said. “But if you do have a problem on a cruise ship, it’s magnified very quickly.”

Comforting statistics aside, there are several steps passengers can take to minimize the chances of getting sick during a cruise.

Among them:

* Pick a ship with a good sanitation record. Cruise ships with foreign itineraries that call at U.S. ports are subject to two unannounced inspections by the CDC every year.

The inspections, which are paid for by the cruise lines, cover such areas as food and water handling, general cleanliness and employee hygiene. A passing grade is 86 of 100 points; ships that score lower than 86 are reinspected within two months. Experts caution that a failing score doesn’t mean a gastrointestinal outbreak is imminent; nor does a high score guarantee safe passage.

The Viking Serenade scored a 92 on its most recent inspection in July, and hasn’t received a failing score in at least five years, a Royal Caribbean spokesman said. But passengers would do well to avoid ships that show a pattern of low sanitation scores, experts suggest.

CDC test results are published twice a month in its “Summary of Sanitation Inspections of International Cruise Ships,” known colloquially as the “green sheet.” Many travel agents keep these on file. For a copy of the most recent inspection report on a specific ship, contact the Chief, Vessel Sanitation Program, National Center for Environmental Health, 1015 North America Way, Room 107, Miami, Fla. 33132; or fax your request to (305) 536-4528.

* Watch what you eat and drink--particularly on shore.

“I’m not going on a cruise and not drink the water or eat the food. That’s overkill,” said Dr. Stephen Brunton, director of family medicine at Long Beach Memorial Medical Center, and a former cruise ship physician. But when passengers go ashore, particularly in underdeveloped countries, they should be leery of raw food, salads and uncooked vegetables, dairy products and undercooked meats and fish, experts say. Eating raw or undercooked foods on board also carries a risk.

In May, the CDC asked cruise lines to post information on their ships, addressing the dangers of consuming raw or undercooked poultry, meat and shellfish. Many ships are now complying, said Donald Turner, chief of the CDC’s Vessel Sanitation Program. * Before a trip, ask about the quality of medical care on board, particularly if you’re in poor health. While a recent U.S. Coast Guard survey found that all major cruise lines sailing from American ports have emergency care facilities, no international or U.S. regulations cover medical personnel or facilities on cruise ships, said Turner.

As a result, there are “incredible variations” in the level of medical personnel training, quality of equipment and documentation of on-board illnesses and injuries, said Dr. Carter Hill, medical director of Holland America Line and Windstar Cruises, and chairman of the Cruise Ship and Maritime Medicine section for the American College of Emergency Physicians.

The section has compiled a list of 10 recommendations for cruise ship medical care--including a medical staff (licensed physicians and nurses) experienced in primary and emergency care, emergency medical equipment, supplies and medications and a staff fluent in English and familiar with U.S. or Canadian medical procedures, if the ship sails from North American ports.

If you have chronic conditions that might require medical attention while you’re on board, ask your travel agent to check on the level of care available. Hill suggests such passengers bring along a copy of medical records and EKG, if applicable.

* Passengers should check that their medical insurance covers them outside the United States, and that they are covered for a medical evacuation.