Virus Rattles Cruise Industry and Health Officials

By DENISE GRADY

his article was reported by Joseph B. Treaster, Dana Canedy and Denise Grady and was written by Ms. Grady.

The reports from the Caribbean cruise ship Oceana began arriving at the Centers for Disease Control and Prevention late on Tuesday. By Wednesday night, the picture was disturbingly familiar: 117 on board were violently ill with vomiting and diarrhea, the same symptoms that had laid low passengers on three other ships in the last two months.

Advertisement

A common and highly contagious infection, caused by a germ known as a Norwalk-like virus, has been confirmed on two of the ships and is suspected on the other two. Since October, the virus has sickened at least 900 passengers and crew members on cruise ships.

The outbreaks are creating a mystery for federal health officials and are rattling passengers and cruise company executives. Norwalk-like viruses have hit ships before, but health officials said they did not know why the recent outbreaks were occurring, and they said the recent burst of cases appeared to be an increase over previous years.

The nature of the viruses — they are common, hardy, highly contagious and hard to track — raises the possibility that periodic outbreaks on ships may be inevitable, one more risk that the traveling public must factor into the calculation of whether to book tickets or stay home. The tight quarters of a ship provide ideal conditions for contagious germs like Norwalk viruses to multiply.

Rapid turnaround times — often just hours between one cruise and the next — can make it difficult to eliminate stubborn organisms. Sick or recovering passengers, loath to spend their vacations in their cabins, may infect others, as may crew members who work while ill.

Dr. Megan Murray, a Harvard epidemiologist who was a consultant for the Holland America Line on disinfecting its cruise ship Amsterdam, which had outbreaks on four consecutive voyages, said that illness on ships may be a reflection of the many outbreaks now occurring on land. Scientists said the recent patterns of shipboard cases indicated that the illness was coming not from food or water on the ship, but from infected passengers or crew bringing the virus onto ships. "Any time you take people and put them together in close quarters and they have infection, it spreads," Dr. Murray said. "I think it's a fact of life. It will continue to happen."

The possibility of further outbreaks unnerves the cruise industry, an $11 billion a year business that was hit hard by fears of terrorism after Sept. 11 but rebounded strongly. Even though only a tiny proportion of cruise passengers have gotten sick so far — 1,000 or so out of more than 7 million projected for this year — each outbreak causes a stir.

"If this keeps happening, people are not going to want to get on those ships," Dean Gianoukos, an analyst at J. P. Morgan, said.

Cruise executives say there has been no big drop in bookings. But in the last five days the stock prices of several major cruise companies have fallen sharply.

"I think people are nervous about what could happen to bookings because of the sickness," Mr. Gianoukos said.

Once the virus boards a ship, it can spread rapidly and become extremely hard to eradicate. It can contaminate surfaces, carpets and upholstery, linger for weeks, resist routine cleaning and flare up on cruise after cruise.

The Amsterdam and the Disney Magic each canceled a cruise recently so the ships could be scrubbed, steamed and disinfected with bleach and other chemicals. But there is no reliable test to detect the virus on surfaces, so the only way to tell whether a ship has been disinfected is to send it out again and see whether anyone gets sick.

The VirusA Common Infection
That Is Easily Spread

At least 23 different strains of Norwalk-like virus can infect people. Most adults have been exposed to at least one, Dr. Murray said. The name comes from Norwalk, Ohio, where the first strain to be identified caused an outbreak of gastrointestinal illness in 1968. The virus was identified later from stored stool samples.

viruses are spread by what scientists call the fecal-oral route. As the unpleasant term suggests, transmission occurs when virus particles from an infected person's stool or vomit find their way into another person's mouth. That can occur when infected people fail to wash their hands after using the toilet and then touch other people, common surfaces or food. In some outbreaks, though apparently not the recent ones on ships, people have caught Norwalk from eating raw or undercooked shellfish taken from sewage-laden waters. They can then pass the infection to others.

Advertisement

Cruise passengers have been advised that they can reduce the risk of infection by washing their hands frequently and keeping their hands out of their mouths to avoid ingesting viruses they may have picked up from touching doorknobs and railings.

Handwashing does not protect against incidents of "public vomiting," which have occurred on ships because the illness can cause sudden nausea, Dave Forney, head of the vessel sanitation program at the Centers for Disease Control and Prevention, said.

It takes only a small dose of the virus, 100 particles or even fewer, to make a person sick, according to studies of people who volunteered to become infected by drinking a stool filtrate.

The incubation period is usually a day or two, and the illness lasts a few days, causing nausea, vomiting, stomach cramps, diarrhea and sometimes fever and headache. Dr. Marc-Alain Widdowson, an epidemiologist at the disease centers, said that the infection can make a person vomit 10 to 20 times in one day. Most people recover quickly, but those who are frail or are already ill can become dangerously dehydrated.

People become immune after being infected, but the immunity probably does not last more than a few months, Dr. Widdowson said. Still, they appear to eliminate the virus from their bodies, and do not become carriers. Immunity to one strain does not protect against others.

On land, the vast majority of people with gastrointestinal illness like that caused by Norwalk viruses recover on their own and do not see a doctor. Many think they had a "stomach flu," though there is no such thing; technically, the flu is a respiratory virus. Researchers estimate that there are 76 million cases a year of gastrointestinal illness in the United States and that Norwalk-like viruses cause 23 million of those cases, Dr. Widdowson said.

"We have several outbreaks a month of Norwalk," he said, adding that since January, the disease centers had confirmed 37 outbreaks in the United States, including those on ships. The number is typical, he said.

The cruise-ship cases may stand out because they are more likely than the ones that occur on land to be reported to health officials. The C.D.C. requires that medical officers on ships report cases of gastrointestinal illness, and it may investigate and conduct diagnostic tests if the infection hits at least 2 percent of the passengers.

Outbreaks occur in many other places where people live together in close quarters, like camps, military ships, army barracks, nursing homes, hospitals and day-care centers. Troops have suffered outbreaks in Afghanistan and in the Persian Gulf war.

Last month, 150 people became ill from Norwalk infections after eating in a Salt Lake City restaurant called the Chuck-A-Rama.

In the past two months, Edmonton, Alberta, has recorded 29 outbreaks, as compared to only 10 all last winter. Officials cannot explain the increase.

Infected food handlers can start a wave of disease that sickens extraordinary numbers of people. Dr. Murray cited an outbreak in Sweden that ultimately affected 2,000 people; it started with one sick kitchen worker.

Last July, a Norwalk outbreak felled 388 passengers on the Ryndam on two consecutive cruises to Alaska. The ship was taken out of service to be disinfected. Then in October, 193 passengers on the Amsterdam became sick on a cruise through the Panama Canal that had begun in Seattle. Three more Amsterdam cruises out of Port Everglades brought down another 261 passengers, and the shipping company decided to cancel a cruise in order to swab and steam clean the Amsterdam. (Both the Amsterdam and the Ryndam are owned by the Holland America Line, which is owned by the Carnival Corporation.) At about the same time, the Disney Cruise Line/> began disinfecting its 2,500-passenger Disney Magic after 483 passengers on two cruises became ill.

On Dec. 4, the disease centers reported that 114 passengers and 3 crew members were ill on the Oceana. The Oceana, a new ship, was on only its third cruise. Mr. Forney said all the ship's passengers were from the United Kingdom, and that all the sick ones had flown to Florida on the same charter flight. Some, he added, got sick during their first day on the ship, meaning they must have contracted the virus before boarding.

"It makes you wonder," he said.

Executives at Carnival said that while they pulled the Ryndam out of service after two bouts of the virus, their usual approach has been to keep operating the ships while dealing with outbreaks.

Passengers from affected cruises on the Amsterdam and the Ryndam have filed class-action suits against Holland America, saying it should have taken the ships out of service sooner.

Tim Gallagher, a spokesman for Carnival, said that in March, 61 passengers on Carnival's ship, Pride, fell ill with a stomach virus. "We caught it early in the cruise," he said. "We were in touch with the C.D.C. and instituted our aggressive housekeeping procedures right away. On the next cruise we had three cases, and on the one after that it was zero."

Advertisement

A former executive for Carnival Cruise Lines, who spoke on condition of anonymity, said that financial factors play as much a role as concern for passengers when decisions are made about taking a ship out of service.

"The consideration is that if 200 people came down with Norwalk and they had to give 200 free replacement cruises, how will that affect the bottom line — versus canceling the entire cruise" and having to compensate all 2,000 passengers, the executive said. "That may sound harsh but I think that's one of the realities."

Cleaning the Ships

15 Minutes a Room
Between Some Cruises

When a ship carrying 2,000 passengers finishes a cruise, crews may have only three to four hours — 15 minutes a room — to clean the ship before the next round of passengers board.

Industry executives say that is enough time, because ships are cleaned continuously while they are sailing, with 30 to 40 people constantly cleaning.

But executives also say that given the outbreaks, the ships are being cleaned more frequently, and with stronger chemicals.

"Every hour, we clean the handrails, elevator buttons, counters, flat surfaces, exercise equipment," said Manny Rivas, a manager of public health matters at Royal Caribbean Cruise Lines.

But Dr. Murray said that scientists are not sure which disinfectants kill Norwalk-like viruses, and that more research is needed to find out. She said that steam-cleaning carpets and upholstery is thought to do the job, but only if the carpeting can be heated up to 160 degrees Fahrenheit, and not all equipment can do that.

So far, the best way to disinfect a ship seems to be to take it out of service for intensive cleaning. The combination of scrubbing and keeping people away seems to break the cycle of transmission, Dr. Murray said.

Susan McClure, a spokeswoman for the disease control centers, said the agency works closely with cruise lines to ensure that they comply with its vessel sanitation program. Every ship with a foreign itinerary and 13 or more passengers that visits American ports is subject to unannounced, twice-yearly by the centers.

Inspections may take five to eight hours, and results are published on the center's Web site. Among other things, ships are graded on their handling of food and drinking water and maintenance of spas and pools.

The Passengers
Despite Outbreaks,
Ships Are Sailing Full
 

Even as the outbreaks have widened, people have continued filling the ships. On Monday, after Carnival's ship Fascination docked with nearly 200 of 2,000 passengers ill, the ship was given a more intense cleaning than usual and loaded once again for four days at sea.

Mr. Gallagher, the Carnival spokesman, said passengers were offered a full refund if they chose not to sail. Only about 100 of the 2,150 passengers took the refund.

Analysts and the cruise lines say the extra costs and losses associated with canceled sailings and cleanups have not had a major impact on the companies' profits. Mr. Gianoukos, for example, estimated that the Holland America Line lost about $2 million in revenue during the 10 days the ship was out of action. That compares with annual revenues for the parent company, Carnival, of $4.54 billion last year.

But analysts also said the cruise lines were at a crucial point in their sales cycle, and bad news could do real damage.

People begin to dream about cruising in balmy seas, pina colada in hand, as winter sets in across North America and Europe. The heaviest booking period begins in about four weeks and runs through April.

"They usually get 30 percent to 35 percent of their bookings then," said Peter R. McMullin, an analyst in the Boca Raton offices of Ryan Beck & Company, a brokerage firm. "It sets the tone for the whole year."