REGAL PRINCESS

An outbreak of viral gastroenteritis has occurred on board a cruise liner in the Caribbean. Since 12 April 1998, when the ship set sail from the Dominican Republic, 347 passengers and 28 crew members have reported sudden onset of explosive diarrhoea and vomiting. These figures are likely to underestimate the morbidity associated with this outbreak since some people who were symptomatic are thought not to have contacted the ship's doctor. Passengers on two earlier cruises aboard the same ship complained of similar symptoms. Small round structured virus (SRSV) has been detected using polymerase chain reaction on faecal specimens from three passengers who became unwell on a cruise at the end of March. An epidemiological investigation is underway and environmental control measures are being applied.

The introduction of SRSV into the confined space on a ship, by contaminated food or water or an infected passenger or crew member, provides considerable opportunities for spread. In 1995, 378 passengers reported gastroenteritis on four consecutive Mediterranean cruises (1). Epidemiological studies pointed to a continuing outbreak of SRSV transmitted from person to person. The ship had to be cleared of passengers for thorough cleaning and disinfection.

Compiled from Department of Defense and U.S. Navy press releases, media reports, and individual interviews.

The cruiser SOUTH CAROLINA (CGN 37) Departed Norfolk 11 March for local operations, burdened by concerns over an outbreak of Legionnaires` disease. One 22-year-old crewmember fell ill with “acute pneumonia” and died 7 January; blood samples taken following his death tested positive for the disease. Three other crewmembers have become ill but have not been so diagnosed. Although no evidence has been found that a cause is on board the ship, Navy officials aggressively pursued preventative measures, removing most of the crew and cleaning all plumbing and ventilation systems aboard the cruiser.
 

LINK TO THE THE CRUISER USS SOUTH CAROLINA (CGN 37)

Deadly disease strikes Navy ship

Source Media

Norfolk.
When Legionnaires' Disease killed a sailor, the Navy took extra precautions to prevent other cases on the victim's ship before it was allowed to sail this week.
The Navy scoured the USS South Carolina's ventilation system and chlorinated the guided missile cruiser's water system to kill any bacteria that may be associated with the potentially deadly pneumonia.
The South Carolina left Tuesday for training exercises and is to return today. The Navy declined to release the ship's location.

There is no evidence that there's anything contagious on board, said Capt. Adam Robinson, a medical officer with the Atlantic Fleet Surface Force.

The Navy still is awaiting test results of water samples sent to the Centers for Disease Control in Atlanta, he said.
But the breakout raised the question of what the Navy would do should a deadly contagion strike within the confines of a ship hundreds of miles at sea. All ships have doctors or medically trained enlisted personnel who treat sailors on board, while larger ships such as aircraft carriers have their own hospitals, said Lt. Cmdr. John Singley, a Navy spokesman.
Before the South Carolina sailed, medical officers inspected the cruiser as recommended by the CDC.
Navy officials also have encouraged any of the South Carolina's 450 crew members with a 102-degree fever, shortness of breath or a cough to seek medical attention. Those are some symptoms of Legionnaire's disease.

Navy doctors also are tracking cases of upper respiratory problems. Since October, three sailors have been diagnosed with viral pneumonia and two have had bronchitis.
They have recovered or are in the stages of recovery, Robinson said.

A sixth sailor, had just returned from vacation when he became ill and was hospitalized with pneumonia in late November.
The 22-year-old machinist's mate, died on Jan. 7.

He tested positive for the bacteria that causes Legionnaires' disease, which got its name from a 1976 American Legion convention in Philadelphia.

Outbreaks of the illness have been associated with the water in air-conditioning systems, showers and whirlpool baths, among other sources.

Last week, the Navy used its family support group to inform relatives of crew members about the illnesses.
The families are concerned but not panicked, said a ship's ombudsman whose husband is a nuclear machinist's mate on the South Carolina.
Everything is being done and all the steps are being taken to make sure that this is contained.

Six cases in British tourists have been linked to a single ship that was used exclusively by one British tour company for cruises on the Rhine. The first case occurred in July, the second in August, two cases became ill in September, and two in October. Four cases are men, two women (age range 72 to 78 years). None has died. One case with onset of illness in October was admitted to hospital in Germany.

The season for this particular cruise has now ended. The last cruise sailed from 24 September to 8 October with 85 passengers on board. The tour operator has contacted passengers to inform them of the outbreak and advise them to seek medical advice if they develop a respiratory illness.

The ship is Dutch owned and is being investigated by Dutch health authorities. There are no reports of illness among members of the crew. The European Working Group on Legionella (EWGLI) collaborators in Germany and the Netherlands are working closely with EWGLI’s coordinators in London to measure the extent of the outbreak and identify the source of infection. 1997

Rubella among crew members of commercial cruise ships--Florida, 1997.

During April-July 1997, two different commercial cruise lines notified CDC of rubella outbreaks among crew members.
In July 1997, CDC initiated an investigation on one cruise ship to determine the extent of and risk factors for rubella infection among crew members and to assess the potential risk for rubella transmission to passengers-particularly rubella-susceptible pregnant women at risk for giving birth to an infant with congenital rubella syndrome (CRS).
This report summarizes rubella outbreaks involving two cruise ships and the results of the CDC investigation on one cruise ship, which demonstrate that crew members can serve as a susceptible population for rubella infection and should be vaccinated with measles-mumps-rubella vaccine (MMR) if they are not immune.
Although the outbreaks were limited to crew members, cruise ship travel provides an environment conducive to the potential spread of rubella and other infectious diseases among crew and passengers; therefore, women of childbearing age, particularly pregnant women, should be immune to rubella before traveling on cruise ships to reduce the risks for rubella infection and CRS.

MMWR Morb Mortal Wkly Rep 1998 Jan 9;46(52-53):1247-1250

Cyclospora: Canada/USA

The Field Epidemiology Training Program at LCDC is collaborating with CDC Atlanta in investigating an outbreak of Cyclospora cayetanensis infection associated with a cruise.
The cruise ship left Florida on March 29, 1997 travelled to the Grand Cayman Islands, Guatemala and Mexico and returned to Florida on April 5, 1997.
Of the approximately 1,000 passengers, 62 were Canadian from 8 different provinces. Questionnaires are currently being mailed to all passengers to determine illness and facilitate diagnosis and treatment. The source of the infection is under investigation

The bacterium, Legionella, causes the respiratory illness Legionnaires' disease. The disease was first recognized in 1976 during an epidemic of pneumonia that affected persons attending an American Legion convention in Pennsylvania. Persons with Legionnaires' disease typically have respiratory symptoms and often have headaches, confusion, and sometimes diarrhea. The incubation period is typically within 2 to 10 days of exposure. The disease can be diagnosed by several different laboratory tests; however, physicians often do not test persons with pneumonia for Legionnaires' disease; thus, many cases go unrecognized. Approximately 10,000 cases are thought to occur each year in the United States. The illness occurs most commonly in middle-aged and elderly adults, and death may occur in 5% to 15% of patients with the disease. The death rate is influenced by how early antibiotics are given to persons with the disease and by the presence of preexistent health problems in the patient. Legionnaires' disease is not transmitted from person to person. It occurs when a person inhales aerosols or microscopic droplets of water contaminated by Legionella organisms. Cooling towers, evaporative condensers, heat- rejection devices, showers, whirlpool spas, respiratory therapy equipment, and a misting machine used in the produce section of a grocery store have been identified as sources of Legionella in outbreak investigations.

Since the bacteria are commonly present in aquatic environments, simply identifying Legionella in the water of an aerosol-producing device does not, by itself, implicate that device as the source of the disease. Interviews of patients can help generate hypotheses about exposure risks. Case-control studies which compare exposures of ill persons with those of well persons are useful for evaluating the hypotheses and identifying the source. Once the source is identified, a few methods are available for decontaminating the implicated device or water system. Chlorine is an effective decontaminant, and high concentrations can substantially reduce the concentration of Legionella in plumbing systems, cooling towers, and whirlpool spas. Circulation of water at high temperatures (above 140oF) can also be useful for decontaminating plumbing systems.

Cases of pneumonia have been detected among passengers of nine separate week-long cruises on the cruise ship Horizon (Celebrity Cruise Line) embarking from April 30 to July 9. Sixteen confirmed cases of Legionnaires' disease and 34 additional cases of pneumonia, for which the diagnosis of Legionnaires' disease is under investigation, have been identified. One person died and four persons were placed on ventilators.

The investigation on the cruise ship Horizon began on July 15 when the New Jersey State Department of Health notified CDC of six persons hospitalized with pneumonia who had recently traveled between New York City and Bermuda aboard the ship from June 25 through July 2. During the evening of July 15, Legionnaires' disease was diagnosed in three of these former passengers. To obtain information about the illnesses and potential sources of exposure for Legionnaires' disease, a questionnaire developed by CDC and a health warning were distributed on July 15 to the passengers and crew of the ship. On the morning of July 16, three CDC epidemiologists met aboard the Horizon with the staff of the cruise line. The ship's captain and staff provided an overview of the ship, including the ventilation and water systems. Two of the CDC physicians sailed with the Horizon to continue CDC's investigation.

CDC investigators collected water samples from potential sources of Legionella, including tap faucets, showers, and whirlpool spas. The ship's three whirlpool spa tubs had been drained and cleaned before docking, a practice reported to be routinely performed at the end of each cruise. Water used for the whirlpool spas remained only in the overflow tanks and in the whirlpool filtration system. There were no other potential recognized sources for Legionella on the vessel.

The preliminary investigation could not determine whether the source of illness among former passengers was aboard the ship, in ports of call, or due to exposures before embarkation. On the afternoon of July 16, to minimize the potential for transmission aboard the ship while the investigation continued, public health officials recommended 1) treating the ship's water system with high levels of chlorine; 2) discontinuing use of the whirlpool spas; 3) continuing collection of samples from environmental sources for laboratory investigations; 4) continuing epidemiologic investigation of the ship; and 5) distributing information on the risk of developing Legionnaires' disease to passengers who were to embark on the cruise beginning July 16.

The ship departed on Saturday evening, July 16. In conjunction with State and local health departments, investigations to determine the magnitude of the outbreak, to identify the source(s) of transmission, and to determine interventions to prevent further illnesses were continued.

To determine the magnitude of the outbreak, a surveillance network was established with State health departments in New York, New Jersey, Connecticut, and Pennsylvania, and with the New York City Health Department. Approximately 80% of the passengers of the June 25 cruise were residents of these five jurisdictions. In addition, State epidemiologists in all U.S. states and territories were notified of this outbreak, as were public health officials in Canada and Great Britain. Celebrity Cruises, Inc., provided passenger rosters from cruises sailing on June 25 and July 2, and survey questionnaires were mailed to approximately 3,000 former passengers. CDC's Morbidity and Mortality Weekly Report published information on the outbreak on July 22.

To identify the source(s) of transmission, epidemiologic and laboratory-based investigations were continued. After the Horizon arrived in Bermuda on July 18, a CDC Environmental Engineer and two Senior Sanitarians boarded the ship and joined in the investigation. Additional water specimens from the ship were analyzed at CDC for the presence of Legionella by bacterial culture methods and modern molecular DNA analysis. CDC epidemiologists discussed with the Bermuda Ministry of Health potential sources of transmission of Legionella from areas on the island frequented by passengers from the Horizon. The Acting Medical Director for the Bermuda Ministry of Health provided data indicating no increase in admissions for pneumonia to Bermuda's hospital in the previous months.

Various water samples from the ship were analyzed in CDC laboratories to determine whether specific Legionella species were present. Samples were tested using the polymerase chain reaction (PCR) assay, a method capable of detecting minute quantities of Legionella specific DNA material in samples. The technique cannot determine whether the DNA is from live or dead Legionella bacteria. Microbiologic cultures to allow growth of bacteria are the only method to verify whether bacteria are alive at the time the water samples are taken. On July 19, Legionella pneumophila serogroup 1 (Lp1) DNA was detected in 15 of 27 water samples. Specimens from the whirlpool spa circulation and filtration system and water from a passenger cabin shower were most strongly positive by this DNA test. On July 20, the results of laboratory tests were conveyed to officials of Celebrity Cruise Lines, and the ship's crew began hyperchlorination of the ship's water supply following recommendations from CDC.

CDC collaborated with State and local health departments in an epidemiologic case-control study. A questionnaire was provided to ill (case) and well (control) passengers to identify activities while on the ship and in ports of call that might be associated with risk of disease. Questions were asked about water consumption, exposure to whirlpools, showering, and excursions in Bermuda. Enrollment of passengers into the study ended on July 31 and preliminary analysis indicates that ill passengers were 16-fold more likely to have used the whirlpool spas than well passengers. Presence in the area around the whirlpool spa, without using the whirlpool, was also associated with a 12-fold increased risk of developing Legionnaires' disease. No other activity, on or off the ship, was found to be associated with illness.

In addition to the DNA analysis, water specimens were cultured for Legionella. On July 22, an organism was isolated from water from one of the sand filters used for recirculation of whirlpool spa water. No other sample of water aboard the vessel grew Legionella. The Legionella strains isolated from the sand filter and Legionella isolated from sputum of one of the passengers with Legionnaires' disease were indistinguishable by subtyping methods.

Epidemiologic and laboratory data indicate that the whirlpool spa was the source of transmission of Legionella to passengers on the Horizon; CDC further recommended:

Discontinue use of the whirlpool spas aboard the ship until safe operation can be ensured; Remove the sand filters used for recirculation of whirlpool spa water; and Continue surveillance to identify any additional cases of Legionnaires' disease occurring among passengers traveling on the Horizon.

The owners of the Horizon took measures to eliminate probable exposures aboard the vessel and followed CDC's recommendations regarding procedures to decontaminate the water supply. In both cases, managers from the Horizon and Viking Serenade fully cooperated with CDC's investigation. Further prevention and control activities regarding Legionella aboard cruise ships will be discussed during the October 17, 1994, meeting.

CDC. DBMD Investigates Legionnaires' Disease Outbreak on Cruise Ship. CDC/NCID Focus. September 1994; 4(9):1,10.

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC) - National Center for Infectious Diseases (NCID)

September 1994 / Vol. 4 / No. 9

DBMD Investigates Legionnaires' Disease Outbreak on Cruise Ship

Robert Breiman, Martin Cetron, and Barry Fields,
Division of Bacterial and Mycotic Diseases, coordinated CDC's participation in investigating the first outbreak of Legionnaires' disease on a cruise ship.

As of August 22, 16 passengers had confirmed Legionnaires' disease, 30 others had possible cases, and one person died. Cases occurred during several of the ship's week-long cruises from April 30 to July 9.

CDC was first notified on July 15 that six persons got pneumonia within a week after their return from a June 25-July 2 cruise on the ship. Jo Hofmann and Daniel Jernigan, ElS Officers, traveled to New York that day to work with quarantine officers, staff from the Vessel Sanitation Program, National Center for Environmental Health, and New York City Health Department personnel to determine the cause and extent of the outbreak. They met the ship on July 16, informed passengers about the earlier illnesses, and began an evaluation of the ship's water system. They also conducted a case-control study with the assistance of Pekka Nuorti, ElS Officer, DBMD, and David Ackman, Rosalind Carter, Rita Washko, and Andre Weltman, ElS Officers, Division of Field Epidemiology, Epidemiology Program Office.

The studies showed a strong association between illness and exposure to whirlpool baths on the ship. The whirlpools had already been shut down on July 16 as a precaution. On the basis of laboratory results and discussions with the CDC team, the cruise line also hyperchlorinated the ship's potable water system and removed the whirlpool filters. When DBMD laboratory testing revealed that samples from the ship's water supply contained Legionella pneumophila DNA, the July 16 cruise was aborted in Bermuda, and the ship returned to dry dock in the United States for further decontamination.

Although bacteria of the Legionella genus are present in numerous water sources, it is not clear why they cause disease only occasionally or why they sometimes cause the more serious Legionnaires' disease and sometimes a milder illness known as Pontiac fever. To determine the nature and range of symptoms of passengers on this cruise ship, Dr. Cetron mailed a questionnaire to approximately 4,500 persons who had been on the ship during three previous cruises in June and July Nearly 70% have responded, and the CDC team hopes the data will elucidate the clinical spectrum of Legionella infection. Ongoing surveillance for pneumonia has also been recommended to evaluate the intervention measures.

The outbreak may be a unique event, or it may signal the possibility of future outbreaks of Legionnaires' disease on cruise ships. To discuss the association of Legionella infection with whirlpool spas and to make recommendations for reducing its transmission on cruise ships so that future outbreaks can be prevented, CDC is convening a meeting of health officials, industry experts, and cruise line representatives in October.

The studies showed a strong association between illness and exposure to whirlpool baths on the ship.

Whirlpool spas implicated in the Legionella outbreak on the cruise ship. The spas are drained and cleaned at the end of each cruise.

Jo Hofmann, EIS Officer, DBMD, inspecting sand from the filtration system of the cruise ship's whirlpool spas. Legionella pneumophila serogroup 1 DNA was detected in samples from the filters by polymerase chain reaction.

The outbreak may be a unique event, or it may signal the possibility of future outbreaks of Legionnaires' disease on cruise ships.

Centers for Disease Control and Prevention. Update: Outbreak of Legionnaires’ Disease Associated with a Cruise Ship, 1994. MMWR (August 12) 1994;43(31):574-5.

MMWR

MORBIDITY AND MORTALITY WEEKLY REPORT

August 12, 1994 / Vol. 43 / No. 31

Update: Outbreak of Legionnaires’ Disease Associated with a Cruise Ship, 1994

On July 15, 1994, CDC was notified by the New Jersey State Department of Health of six persons with pneumonia who had recently traveled to Bermuda on the cruise ship Horizon (1). In conjunction with local and state health departments, an investigation was initiated; as of August 10, a total of 14 passengers had Legionnaires’ disease (LD) confirmed by either sputum culture (one patient), detection of antigens of Legionella pneumophila serogroup 1 (Lp1) in urine by radioimmunoassay (seven patients) (2), or fourfold rise in titer of antibodies to Lp1 between acute- and convalescent-phase serum specimens (six patients). Possible cases in 28 other passengers with pneumonia that occurred within 2 weeks after sailing aboard the Horizon are under investigation. Cases have occurred from nine separate week-long cruises during April 30-July 9, 1994.

To identify the source of Legionella sp., a case-control study was conducted, and environmental sampling of the ship’s water system was performed. Exposure to the whirlpool baths was strongly associated with illness (odds ratio=16.4; 95% confidence interval=3.7-72.3). Cultures taken from a sand filter used for recirculation of whirlpool water yielded an isolate of Lp1; this isolate and the clinical isolate had matching monoclonal antibody subtyping patterns (3).

A variety of interventions were completed, including hyperchlorination of the ship’s potable water supply, removal of the whirlpool filters, and discontinuation of the whirlpool baths. Following completion of these interventions, on July 30 the Horizon resumed its weekly sailing schedule from New York City to Bermuda.

Reported by: I Guerrero, MD, Community Medical Center, Toms River; C Genese, MJ Hung, S Paul, MD, H Ragazzoni, DVM, J Brook, MD, L Finelli, PhD, KC Spitalny, MD, State Epidemiologist, New Jersey State Dept of Health. BA Mojica, MD, KJ Mahoney, MSW, RT Heffernan, MPH, Div of Disease Intervention, New York City Dept of Health; SF Kondracki, DL Morse, MD, State Epidemiologist, New York State Dept of Health. ML Cartter, MD, J Hadler, MD, State Epidemiologist, Connecticut Dept of Public Health and Addiction Svcs. JT Rankin, Jr, DVM, State Epidemiologist, Pennsylvania Dept of Health. C Groves, MS, Maryland State Dept of Health and Mental Hygiene. Div of Quarantine, National Center for Prevention Svcs; Office of the Director, National Center for Environmental Health; Div of Field Epidemiology, Epidemiology Program Office; Childhood and Respiratory Diseases Br, Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC.

Editorial Note:
This outbreak represents the first documented instance of LD aboard a cruise ship docking in U.S. ports. Whirlpool spas previously have been associated with transmission of Legionella (4,5); hyperchlorination of water systems and replacement of filter devices have successfully terminated outbreaks of LD linked to whirlpool spas. CDC recommends post-intervention environmental sampling of whirlpool circulation systems in conjunction with ongoing surveillance for cases of pneumonia to ensure the efficacy of these interventions. Suspected cases of LD among Horizon passengers should be reported to CDC through state and local health departments.

Additional recommendations to reduce the transmission of Legionella sp. from whirlpool baths and aboard cruise ships will be the subject of a special meeting of public health officials, LD experts, and members of the whirlpool and cruise line industries; the meeting is tentatively scheduled for the fall of 1994 in Atlanta. Additional information about the meeting is available from CDC’s Office of the Director, National Center for Environmental Health, telephone (404) 488-7093.

References

1. CDC. Outbreak of pneumonia associated with a cruise ship,
1994. MMWR 1994;43:521.

2. Kohler RB, Zimmerman SE, Wilson E, et al. Rapid radioimmunoassay diagnosis of Legionnaires’ disease: detection and partial characterization of urinary antigen.
Ann Intern Med 1981;94:601-5.

3. Joly JR, McKinney RM, Tobin JO, Bibb WF, Watkins ID, Ramsay D. Development of a standardized subgrouping scheme for Legionella pneumophila serogroup 1 using monoclonal antibodies.
J Clin Microbiol 1986;23:768-71.

4. Vogt RL , Hudson PJ, Orciari L, Heun EM, Woods TC. Legionnaires’ disease and a whirlpool spa [Letter].
Ann Intern Med 1987;107:596.

5. Spitalny KC, Vogt RL, Orciari LA, Witherell LE, Etkind P , Novick LF . Pontiac fever associated with a whirlpool spa.
Am J Epidemiol 1984;120:809- 16.

September 1994

Investigators employed practices similar to those used during the Horizon investigation when a second disease outbreak occurred in September, this one aboard Royal Caribbean's Viking Serenade, on a trip from San Pedro, California, to Ensenada, Mexico. Hundreds of passengers and crew became ill with diarrhea and vomiting during the cruise, forcing the ship to return to port in California.
 

Viking Serenade

As with the Horizon outbreak, personnel from NCID and VSP began working immediately with staff of the California health department and cruise line officials to determine the cause and magnitude of the Viking Serenade outbreak. Passengers were given questionnaires asking about their cabin number, dining table number, water consumption, and symptoms and duration of illness. These questionnaires revealed 586 passengers and 24 crew members who were sick. "There may have been more who got sick after leaving the ship," said Dr. Kim Cook, NCID, an epidemiologist who worked on the investigation.

Stool and serum samples from ill passengers and crew were collected and cultured in CDC laboratories. Within a matter of days, Shigella bacteria had been isolated from the samples, indicating an outbreak of shigellosis aboard the ship.

Because Shigella can be spread from food, water or person-to-person, NCID and VSP staff carefully inspected sanitation aboard the ship, especially in areas of food preparation, food service, and child care to see if a problem in one of those areas may have been the cause of the outbreak. According to VSP inspectors, water systems, hot and cold food temperatures, and sewerage systems were in good condition. Although there were minor deficiencies in sanitation, the ship would have received a better than passable score if this had been a chargeable inspection. Before the ship sailed again, Viking Serenade staff corrected all deficiencies that were noted by CDC inspectors.

The source of the outbreak aboard the Viking has not been determined, but investigators are continuing to analyze data. "We have sent out over 700 questionnaires to passengers to try to determine the mode of transmission," Dr. Cook said, "A preliminary analysis of questionnaire data does not show any statistical association between illness and the consumption of ship's water," he said, adding that a foodborne source was likely with the possibility of secondary person-to-person transmission.

Source CDC

APRIL 4th 1997

MS Royal Odyssey

Norwegian Cruise Line has cooperated fully with CDC in all aspects of this investigation. Their actions have been responsible and appropriate. All recommendations and counsel have been followed expeditiously.

During the first cruise (March 4-14, 1997) preliminary investigations revealed that passengers and crew aboard had reported diarrhea illness. The subsequent investigation found small round structured viruses (SRSVs), which included Norwalk or Norwalk-like viruses. While the ship's staff indicated they had followed CDC's recommendations for decontamination and prevention of subsequent cases, additional diarrhea cases continued to be reported. During this last cruise (March 25 - April 4, 1997), approximately 39% of the passengers and 17% of the crew reported at least one episode of vomiting and/or diarrhea.

Norwalk virus is a gastroenteritis illness and is usually associated with contaminated water and foods. General symptoms are nausea, vomiting, diarrhea, and abdominal pain.

CDC epidemiologists are at the ship's port in Miami, Florida and continuing the investigation. All passengers disembarked this morning.

CDC became involved in inspecting cruise ships in the 1970's as a cooperative effort with the cruise ship industry. The program assists the industry in fulfilling its responsibility for developing and implementing comprehensive sanitation programs in order to minimize the risk for gastrointestinal diseases.

CDC Office of Communication Media Relations Division: 404-639-7290 or 404-639-2888 and request on-call press officer. ---------------------------------------

This is reproduced here in relation to the recent outbreak on a different cruise ship from which Norwalk virus was also isolated. Note that this advisory was issued after outbreaks on 3 successive cruises. The 1998 outbreak also spread over 3 successive cruises, but since the vessel operates out of Santo Domingo, Dominican Republic, under a British flag, I suppose CDC has no jurisdiction, and is therefore unable to issue a travel advisory, even to protect U.S. citizens from possible exposure.

This illustrates an aspect of travel health that needs addressing. In a case such as this where British, Canadian and American passengers are involved, Filipino crew, and destinations in the Caribbean and Mediterranean, it should be possible for advisories to go out to all countries involved, in the interest of public health.

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC) - National Center for Environmental Health (NCEH) - Vessel Sanitation Program (VSP http://www.cdc.gov/nceh/programs/sanit/vsp/advis/advis.htm

Source: UK Press Association, 15 Apr 1998

More than 100 travellers including 29 Britons have been struck by a mystery bug which has hit the same cruise ship three times, it was disclosed today. Despite attempts by operators Airtours to destroy the virus by deep cleaning the luxury ship Sundream after 117 tourists were taken ill on two seven-day cruises, the bug has reappeared.

Five passengers and two crew sailing between the Caribbean and the Mediterranean are currently suffering from symptoms including stomach cramps, dizziness, vomiting and diarrhoea. The victims had all embarked from the Dominican Republic, scene of a recent travellers' health scare. But Airtours - based in Rossendale, Lancashire - said the problems on board the ship were unconnected to the situation on shore. They believed the bug originated in north America and was spread by Canadian passengers.
 

M S Sundream

One Sundream passenger back in the UK after being hit by the bug said it ruined her holiday and she is now demanding compensation. [Name deleted], 44, from Hyde, Greater Manchester, said she and her 52-year-old husband were both taken ill before they boarded the vessel. "It was awful, there was a lot of pain from stomach cramps and we were being sick, vomiting and having to go to the loo all the time. "The symptoms were coming and going every day. "The worst part was that we'd prepared so well, getting books out of the library to check on the best places to visit on the island excursions, but we couldn't go on any of them. "If we made it to the dining room some days it was half-empty because so many people were ill. I talked to people and it was all the same symptoms - cramps, dizziness, throwing up and going to the loo. "I was annoyed too after talking to the staff on board and finding out it had been going on before, just the other week. "I certainly want my money back at least. The disappointment and the stress just ruined it for me," she said.

Richard Carrick, marketing director of Airtours, said: "The illness people are experiencing seems to be a form of gastric flu. "We have carried out tests over the last 10 days and environmental specialists have also inspected the ship and they have demonstrated the problem is not associated with the food, water or air conditioning, which is typically the sorts of areas where you might pick up this sort of bug." He said the current outbreak was concentrated in customers from Canada and this led the company to believe the bug had been brought on board by passengers. They have been advised to stay in their cabins to prevent the illness spreading and the situation was being "closely monitored". He said: "In the big scheme of things we are looking at a total passenger complement of 1,500 and it is a relatively small number affected, although that's not taking anything away from the seriousness of the situation." Claims for compensation would be looked at on an individual basis, he added.

The health scare has led to two tour operators dropping the Dominican Republic as a destination. Airtours has stopped using four hotels over hygiene concerns and there are fears of a long-term slump in the number of British visitors.

J Infect Dis 1998 Apr;177(4):1041-1045

An outbreak of Brainerd diarrhea among travelers to the Galapagos Islands.

In 1992, an outbreak of chronic diarrhea occurred among passengers on a cruise ship visiting the Galapagos Islands, Ecuador. Passengers (548) were surveyed, and stool and biopsy specimens from a sample who reported chronic diarrhea were examined.
On completed questionnaires, returned by 394 passengers (72%), 58 (15%) reported having chronic diarrhea associated with urgency (84%), weight loss (77%), fatigue (71%), and fecal incontinence (62%). Illness began 11 days (median) after boarding the ship and lasted 7 to >42 months. Macroscopic and histologic abnormalities of the colon were common, but extensive laboratory examination revealed no etiologic agent. No one responded to antimicrobial therapy.
Patients were more likely than well passengers to have drunk the ship's unbottled water or ice before onset of illness and to have eaten raw sliced fruits and vegetables washed in unbottled water. Water handling and chlorination on the ship were deficient. Outbreaks of a similar illness, Brainerd diarrhea, have been reported in the United States. Although its etiology remains unknown, Brainerd diarrhea may also occur among travelers.

Mintz ED, Weber JT, Guris D, Puhr N, Wells JG, Yashuk JC, Curtis M, Tauxe RV

Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.

Epidemiologic Notes and Reports

Acute Respiratory Illness Among Cruise-Ship Passengers -- Asia ============================================================== SOURCE: MMWR 37(4);63-6 DATE: Feb 05, 1988

In late October 1987, influenza A(H3N2) was isolated from a throat culture specimen collected from an 83-year-old woman in Los Angeles County, California. The patient had been hospitalized with pneumonia and congestive heart failure 1 day after returning from a 19-day tour and cruise in Asia. When interviewed in November, the woman said many tourists had been ill with an acute respiratory illness (ARI) while aboard the cruise ship. The patient's physician became ill with an ARI 36 hours after examining the woman. Influenza A(H3N2) virus was also isolated from his throat culture. The tour group convened in Hong Kong on October 7 and toured the city for 2 days before boarding a cruise ship on October 9.
The ship departed the following day and visited Shanghai, People's Republic of China (PRC), on October 13-14; Pusan, Korea, on October 17; and Yantai and Qinhuandao, PRC, on October 19 and 20, respectively.
The tour group disembarked at Qinhuandao for an overland journey and a 3-day visit in Beijing before returning to the United States by air.
A telephone survey was conducted to determine the impact of ARI among thecruise-ship passengers. There were 427 passengers (median age, 66 years): 222 were residents of California, 201 were residents of 31 other states and the District of Columbia, three were from foreign countries, and the residence of one was not identified. Between November 21 and December 15, attempts were made to contact each of the 423 U.S. residents by telephone.
A standard questionnaire was administered to the 277 (65%) persons who were interviewed; 19 persons (5%) refused to be interviewed; and 127 (30%) could not be reached. One hundred four (38%) of the persons interviewed reported an ARI during the period October 1-30. Symptoms for 94 of these persons included fever or feverishness with either cough or sore throat; 10 persons reported cough, sore throat, and myalgias. The peak of the outbreak occurred on October 20 (Figure 1), 6 days after the ship's visit to Shanghai and 3 days after the visit to Pusan, Korea. Seven passengers (2.5%) reported that they were diagnosed by a physician as during the period October 1-30. Symptoms for 94 of these persons included fever or feverishness with either cough or sore throat; 10 persons reported cough, sore throat, and myalgias. The peak of the outbreak occurred on October 20 (Figure 1), 6 days after the ship's visit to Shanghai and 3 days after the visit to Pusan, Korea. Seven passengers (2.5%) reported that they were diagnosed by a physician as having pneumonia after their return home; five (71%) of the seven were hospitalized. No deaths were reported. To determine the potential for secondary spread in the community, passengers were asked to identify nontourist contacts who had onset of an ARI within 3 days of the tourist's return home. Ten (36%) of the 28 households with a tourist who reported late onset of symptoms* reported that at least one nontourist contact had become ill. Two (5%) of the 42 households without a patient with late onset of symptoms reported contacts who had become ill (relative risk = 7.5, 95% confidence interval = 2.3 to 24.5). Data from persons over 64 years of age were analyzed separately because this age group is considered to be at increased risk for complications following influenza infection (1). To decrease this risk, the Immunization Practices Advisory Committee (ACIP) recommends that all persons over 64 receive influenza vaccine annually (1). In calculating vaccine efficacy, investigators assumed that 1) all cases of ARI were due to influenza and 2) risk factors for influenza-related complications were similar for the vaccinated and unvaccinated groups. The attack rate among the 36 tourists who were over 64 years of age and had received the 1987-88 influenza vaccine in August or September 1987 was 36%; the rate was 37% among the 127 unvaccinated travelers in this age group. Duration of illness, defined as the number of days before patients felt that they had returned to their normal level of health, did not differ significantly between the two groups. The mean duration was 19.3 days for the vaccinated group and 21.9 days for the unvaccinated group (t test = 0.62, pless than 0.40). The hospitalization rate was the same (3%) among the vaccinated and unvaccinated passengers in this age-group. Antigenic analysis of the isolates from the two culture-confirmed index cases was performed by reciprocal hemagglutination-inhibition tests with sera taken from infected ferrets during the convalescent stage of illness. The results indicate that the isolates are type A(H3N2) variants similar to influenza viruses isolated in Asian and Pacific countries since April 1987 (2).
Reported by: CD Berlingberg, MD, FH Kahn, MD, Los Angeles; LY Chun, MPH, JM Cruz, G Gellert, MD, MP Giles, MS, L Mascola, MD, FJ Sorvillo, MPH, M Tormey, MPH, SH Waterman, MD, Los Angeles County Dept of Health Svcs; RA Murray, DrPH, KH Acree, MDCM, MPH, JD, Acting StateEpidemiologist, California Dept of Health Svcs. Office of the Director, Influenza Br, Div of Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note: This is the second outbreak of ARI among U.S. tourists who have traveled aboard cruise ships in the Pacific Basin during the last 6 months.
The previous outbreak was also identified following reports of a traveler who was acutely ill upon returning from a trip and for whom influenza A(H3N2) infection was confirmed (3).
The extent of illness among nontourist household contacts in the present outbreak suggests that an infectious agent that is transmitted from person to person was responsible. The following evidence suggests that influenza virus was involved: 1) influenza A(H3N2) was isolated from a tourist and her physician, 2) viruses from these index cases were antigenically similar to strains present in Hong Kong (4) and Shanghai during September 1987 (Health and Antiepidemic Station, Shanghai, PRC, unpublished data) and 3) the sharp peak in the epidemic curve and high attack rates are typically seen in influenza outbreaks in partially closed settings, including military vessels (5,6), aircraft (7,8), and institutions (9).
Most tourists with ARI had onset of illness in late October and were ill either during the flight home to the United States or within 3 days of returning home. Although the duration of illness following influenza infection for persons over 64 years of age may be longer than the 5-7 days usually experienced by younger adults (10), the longer durations reported in this outbreak may be partially due to travel-related factors such as jet lag. Nevertheless, these data suggest that influenza vaccine did not attenuate illness duration in this group.
There are at least three possible reasons for the lack of vaccine efficacy demonstrated: 1) repeated exposures to infectious persons or different dynamics of transmission (11,12) occurring in a population in a partially closed setting may overcome levels of immunity that might be protective in other settings, 2) some of the illnesses may have been caused by other respiratory pathogens circulating at the same time (13), or 3) an influenza virus representing a clinically significant antigenic drift from the vaccine strain caused the outbreak. The observations in this investigation support the results of laboratory studies (2) that suggest that the A/Leningrad/86(H3N2) component of the vaccine may not provide optimal protection against the strains of virus recently identified in the Pacific Basin and now present in the United States. The need for long-term care facilities housing high-risk patients to develop contingency plans for rapidly initiating amantadine prophylaxis in the event of influenza A outbreaks should be reemphasized (2), particularly in light of continuing reports of influenza A(H3N2) outbreaks in such institutions this winter.

References 1. Immunization Practices Advisory Committee. Prevention and control of influenza. MMWR 1987;36:373-80,385-7.
2. Centers for Disease Control. Antigenic variation of recent influenza A(H3N2) viruses. MMWR 1988;37:38-40,46-7.
3. Centers for Disease Control. Outbreak of influenza-like illness in a tour group--Alaska. MMWR 1987;36:697-8,704.
4. World Health Organization. Influenza. Wkly Epidem Rec 1987;47:359.
5. Olson JG, Ksiazek TG, Irving GS, Rendin RW. An explosive outbreak of influenza caused by A/USSR/77-like virus on a United States naval ship. Milit Med 1979;144:743-5.
6. Ksiazek TG, Olsen JG, Irving GS, Settle CS, White R, Petrusso R. An influenza outbreak due to A/USSR/77-like (H1N1) virus aboard a US Navy ship. Am J Epidemiol 1980;112:487-94.
7. Moser MR, Bender TR, Margolis HS, Noble GR, Kendal AP, Ritter DG. An outbreak of influenza aboard a commercial airliner. Am J Epidemiol 1979;110:1-6.
8. Centers for Disease Control. Influenza activity in civilian and military populations and key points for use of influenza vaccines. MMWR 1986;35:729-31.
9. Patriarca PA, Weber JA, Parker RA, et al. Efficacy of influenza vaccine in nursing homes: reduction in illness and complications during an influenza A(H3N2) epidemic. JAMA 1985;253:1136-9.
10. Barker WH, Mullooly JP. Impact of epidemic type A influenza in a defined adult population. Am J Epidemiol 1980;112:798-813.
11. Alford RH, Kasel JA, Gerone PJ, Knight V. Human influenza resulting from aerosol inhalation. Proc Soc Exp Biol Med 1966;122:800-4.
12. Douglas RG Jr. Influenza in man. In: Kilbourne ED, ed. The influenza viruses and influenza. New York: Academic Press, 1975:395-447.
13. Monto AS, Cavallaro JJ. The Tecumseh study of respiratory illness. II. Patterns of occurrence of infection with respiratory pathogens, 1965-69. Am J Epidemiol 1971;94:280-9. *Less than 4 days before the end of the tour or within 3 days of returning home.

Epidemiologic Notes and Reports

Outbreak of Influenza-Like Illness in a Tour Group -- Alaska ============================================================ SOURCE: MMWR 36(42);697-8,704 DATE: Oct 30, 1987

A 56-year-old Vermont resident began having influenza-like symptoms on August 25, while on a cruise ship off the coast of Alaska. Serum specimens collected from the patient showed a fourfold rise in hemagglutination inhibition titer, indicating infection with a contemporary strain of influenza A(H3N2) virus.
The patient had been one member of a group of 35 (34 residents of Vermont, one from New Hampshire) that had departed for Alaska on August 15 and had spent the period August 22-26 on a cruise ship traveling along the Alaskan coast. Telephone interviews with all group members revealed that 19 (54%) had had a respiratory illness (fever or feverishness, and at least two of the symptoms of cough, coryza, sore throat) between August 23 and September 2; onset was August 25 for seven persons (37%). The mean age of the persons who became ill was 62 years, similar to that of the entire group. Anecdotal reports suggest high rates of respiratory symptoms among the approximately 600 other tourists on the vessel. Further serologic evidence for the occurrence of type A(H3N2) influenza infection among the tourists from Vermont is being sought. No other outbreaks of influenza-like illness or confirmed influenza infections have been reported in Alaska. Reported by: RP LaFiandra, MD, Addison County, Vermont; State Laboratory Directors and Epidemiologists, Alaska and Vermont. Div of Field Svcs, Epidemiology Program Office; Influenza Br, Div of Viral Diseases, Center for Infectious Diseases, CDC.

Editorial Note:

Although additional laboratory evidence of influenza infection is still being sought, it is likely that a cluster of influenza A(H3N2) infections occurred in the tour group from Vermont. Recent reports from the World Health Organization describe the circulation of type A(H3N2) strains in several Asian and Pacific nations from about April to September. Considering the large numbers of people traveling through Alaska who are residents of, or visitors from, countries of Asia and the Western Pacific, importation of the virus into Alaska in the late summer is to be expected. The occurrence of an early outbreak of influenza A(H3N2), coupled with the lack of activity of type A(H3N2) virus in the United States last winter, suggests that this subtype will be at least partially responsible for the influenza activity of the coming season. Traditionally, type A(H3N2) viruses, in contrast to type A(H1N1) viruses, have spread to older persons (as in the Alaskan outbreak) and have been responsible for most mortality and excess hospitalizations, as well as causing increases in clinic visits and absenteeism from the workplace or classroom. Actions to reduce this impact are detailed in the recommendations of the Immunization Practices Advisory Committee (ACIP) (1) and in the proceedings of a recent symposium (2). In particular, these measures include vaccinating persons being treated for cardiopulmonary disease, residents of chronic-care institutions, persons over 64 years of age, and any other persons with underlying diseases that increase their likelihood of having complications from viral or secondary bacterial infections. In addition, physicians, nurses, or family members (including children) who might transmit infections to high-risk persons should be vaccinated. Vaccine should be routinely provided during this season for the above high-risk persons and their close medical or family contacts.These persons should be actively identified and informed about the advisability of pre-winter vaccination against influenza. Pneumococcal vaccination history should also be determined for high-risk persons, and this vaccine should be administered simultaneously with influenza vaccine to persons who have not already received it. Booster doses of pneumococcal vaccine should not be given. For further information at the local level, contact state or county health departments, or the American Lung Association. References 1. Immunization Practices Advisory Committee. Prevention and control of influenza. MMWR 1987;36:373-80,385-7. 2. Douglas RG, ed. Proceedings of a symposium: prevention, management, and control of influenza: a mandate for the 1980s. Am J Med 1987;82(suppl 6A): 1-69.

Epidemiologic Notes and Reports

Gastroenteritis Outbreaks on Two Caribbean Cruise Ships ======================================================= SOURCE: MMWR 35(23);383-4 DATE: Jun 13, 1986

Three outbreaks of gastroenteritis occurred on two Caribbean cruise ships between April 26, and May 10, 1986. More than 1,200 persons developed gastrointestinal illness; no deaths were reported.
At least one of the outbreaks appears to be associated with Norwalk virus. Two outbreaks occurred on two consecutive 1-week cruises of the Holiday, a Carnival Cruise Line ship. Between April 26 and May 3, a total of 392 (25%) of 1,550 passengers and 30 (4%) of 679 crew who completed questionnaires developed gastroenteritis. Eighty-six percent had diarrhea; 62%, vomiting; 36%, headache; and 26%, subjective symptoms of fever.
The outbreak peaked on the fifth and sixth days of the cruise. On the next voyage, from May 3 to May 10, a second outbreak occurred on the Holiday in which 321 (22%) of 1,470 passengers and 48 (7%) of 658 crew developed gastroenteritis. A sanitation inspection initiated by CDC on May 3 revealed deficiencies related to water chlorination record-keeping, food preparation and holding, and potential contamination of food.
A detailed account of these deficiencies was provided to the ship's management at the end of the investigation on May 3, and recommendations were made to prohibit food-service personnel from working while ill and to correct the sanitation deficiencies.
A week later, when the inspection was completed, several deficiencies similar to those of the previous week were noted. The final vessel sanitation inspection score on May 10 was 18 out of a possible 100 points (passing = 85). An outbreak of gastroenteritis also occurred on Holland America Cruises' Rotterdam. Between May 3 and May 10, 405 (37%) of 1,108 passengers and 35 (6%) of 554 crew who completed questionnaires had a gastrointestinal illness. Eighty percent of ill passengers had diarrhea; 78%, vomiting; 41%, headache; and 32%, subjective symptoms of fever.
Mean duration of illness was 2.4 days, and 76% of ill passengers were confined to their cabins during the illness. A sanitation inspection by CDC on May 9 and May 10 revealed numerous deficiencies related to food and water sanitation; the sanitation inspection score was 16 out of a possible 100 points. A detailed account of the deficiencies was presented to the ship's management on May 10 following the inspection, and recommendations were made to prohibit food service personnel from working while ill and to correct the sanitation deficiencies. Bacterial cultures of stool specimens from the first Holiday outbreak did not yield any recognized pathogens. However, an eightfold or greater rise in antibodies to Norwalk virus was demonstrated by biotin-avidin immunoassay (1) in paired sera obtained from three ill Holiday crew members who had suffered gastroenteritis during the April 26-May 3 voyage; Norwalk antigen was detected by biotin-avidin immunoassay in two of six ill passengers from the same voyage. Laboratory studies of specimens and epidemiologic analysis of questionnaires from ill passengers and crew from all three outbreaks are continuing. Reported by Div of Quarantine, Center for Prevention Svcs, Enteric Diseases Br, Div of Bacterial Diseases, Respiratory and Enterovirus Br, Div of Viral Diseases, Center for Infectious Diseases, CDC.