Epidemiologic Notes and Reports Gastroenteritis Outbreaks
on Two Caribbean Cruise Ships
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.
Editorial Note
Editorial Note: Outbreaks of gastrointestinal illness on cruise
vessels have been caused in the past by contaminated water and by
food
consumed on the ships or on shore visits (2). Person-to-person
transmission has also been strongly suspected on some occasions--in
one case, in the setting of repeated outbreaks on consecutive
cruises
(3).
Laboratory findings implicated Norwalk virus as the pathogenic
agent on the first of the Holiday outbreaks. However, all three
outbreaks had epidemiologic features characteristic of epidemics of
Norwalk virus gastroenteritis. These include: (1) a high attack
rate
in adults; (2) a high frequency of vomiting; (3) short duration of
illness; and (4) absence of identified bacterial pathogens (4).
It is not yet clear whether food or water were vehicles of
infection in these outbreaks or whether sanitary deficiencies
contributed to the risk of outbreaks of viral enteric disease on
these
cruise ships.
References
Gary GW, Kaplan JE, Stine SE, Anderson LJ. Detection of
Norwalk
virus antibodies and antigen with a biotin-avidin immunoassay.
J
Clin Microbiol 1985:22:274-8.
Gunn AG, Terranova WA, Greenberg HB, et al. Norwalk virus
gastroenteritis aboard a cruise ship: an outbreak on five
consecutive cruises. Am J Epidemiol 1986:112:820-7.
Kaplan JE, Gary GW, Baron RC, et al. Epidemiology of Norwalk
gastroenteritis and the role of Norwalk virus in outbreaks of
acute, non-bacterial gastroenteritis. Ann Int Med
1982:96:756-61.
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