Cruise Ship Analysis
Case
An investigation is being launched into the outbreak of a diarrheal illness aboard
the cruise ship Warped Imagination bound for Miami from a Caribbean voyage. In
accordance with VSP protocol, the chief medical officer on board the ship has kept a log
of illness among the crew and passengers. Sick passengers and crew were instructed
to begin a BRAT diet (bananas, rice, apple sauce, tea, and toast). Normally a formal
count would be presented to the VSP 36 hours prior to the arrival in the US; However,
on the 5th day of the trip, a total of 67 cases of diarrheal illness had been recorded
among the 2500 passengers, and 3 cases of a similar illness among the 1200 crew.
Afflicted crew members and all food handlers have been removed from duty. It is now
the 6th day of the trip and, since the caseload has reached the 2% threshold for
passengers, the medical staff has filed the mandatory report of the situation to the VSP.
The ship has made ports of call at Key West; Ocho Rios, Jamaica; Cozumel, Mexico;
Belize; And Grand Cayman. The remaining ports of call up and canceled and the ship is
en route to Miami as the capacity of the medical staff to provide care may soon be
exceeded by the caseload of victims requiring IV therapy. The captain expects to make
it to Miami within about 48 hours provided the weather cooperates. The first case of the
illness was logged on the second day of the cruise about four hours after departing from
Ocho Rios. The index case is a 26-year-old newlywed white female from Philadelphia.
Her husband has not experienced any symptoms. The wedding was a day prior to their
departure from Philadelphia. Their only meal of the day of the wedding was a catered
dinner of chicken and beef BBQ, mashed potatoes, mixed steamed vegetables, a
tossed salad, wedding cake, fruit punch, and a glass of champagne. The caterer also
Cruise Ship Analysis
provided a box of leftovers which is a couple snacked on that evening and again just
prior to leaving for the airport on the day the cruise began. They consumed only the
complementary Coke and pretzel snacks during their flight between the time they left
home and the time they had boarded the ship went to the buffet as soon as they could
the couple disembarked at Key West, the first port of call where they ate Key Lime Pie
and coffee. They had no water, alcoholic beverages, or other food while ashore. That
evening they were the first passengers to eat from the buffet on the ship. The woman
was feeling a bit of malaise and wanted to retire early period the following day, the
couple had a light breakfast of fruit, yogurt, toast, and coffee aboard the ship just before
making the port of call Jamaica. The woman claims to have no appetite that morning
and while ashore only slipped a bottle of water acquired from the ship. She consumed
no food in Ocho Rios. Her husband had a cola and saltfish. Ten additional cases were
diagnosed by the medical staff on the 4th day of the voyage and a total of 70 cases were
either diagnosed or self-reported by the 5th day. The predominant symptoms reported
are vomiting and diarrhea. A low-grade fever is variable. Everyone afflicted, including
the index case, continued to have intermittent diarrhea and loss of appetite when the
initial report was made to VSP.
Comprehensive Data Analysis
Based on the data provided, there were no onset of cases aboard the ship on
day one period on day two there was one new passenger case day three there were no
new cases. On day four, there were seven new passenger cases and three new crew
cases. On day five, there were 59 new passenger cases. The sum of the data collected
Cruise Ship Analysis
regarding food consumption included 32 various foods. According to the CDC,
foodborne illness symptoms typically begin within six to twenty-four hours after
consumption. 1 Due to the fact that the index case did not consume tea or fountain
drinks on day one or two, they can then be ruled out as the cause. Unfortunately, there
is a slight lapse in data which in turn means that there are several potential causes for
the foodborne illness. However, because of the time the index case became ill the
likelihood that it is caused by something that was eaten at the buffet increases. This
means that there are many potential causes of the illness including but not limited to
cantaloupe, watermelon, pineapple, papaya, kiwi, carrots, green beans, applesauce,
yogurt, coleslaw, and grapefruit.
Statistical Calculations
There is a significant amount of food items on the list consumed by crew
members and passengers, both ill and healthy. Based on the data table the highest
percentage of passengers who became ill consumed watermelon cantaloupe and
creamed corn. 5.8% of crew and passengers who consumed watermelon on day one
became ill, 3.5% of crew and passengers who consumed cantaloupe on day one
became ill, and 3.2% of crew and passengers who consumed creamed corn on day one
became ill. Due to the high percentages of these food items, they are the most likely to
have caused the illness. Upon further investigation, the increase in illness after
consumption of watermelon goes to 7.2% on day two, 12.2% on day three, and 8.5% on
day four. No other food items increase in this way. The specific attack rate for
watermelon on day one is 5.8%, day two is 7.2%, day three is 12.2%, day four is 8.5%,
and 0% on day five. This means that watermelon is the most likely cause of the illness.
Cruise Ship Analysis
Probable Source of Outbreak
Based on the data above it is likely that the outbreak is related to the melons
sourced on the ship. Many people assume that because melons have a rind and the
rind is not eaten It does not need to be washed like other foods. However, there have
been many cases of melons causing foodborne illnesses. One outbreak of salmonella is
related to precut melons according to the Food and Drug Administration, “The United
States Food and Drug Administration (FDA), along with the Centers for Disease Control
and Prevention (CDC), and state and local partners, is investigating a multistate
outbreak of Salmonella Carrau illnesses linked to pre-cut melon products. These
products contain cantaloupe, honeydew, or watermelon, or maybe mixes of some or all
of these melons and other pre-cut fruit”.2 because of a detailed examination of the index
cases food diary, we are able to see a diverse consumption pattern mainly consisting of
fruit and melons. This is a critical baseline for the potential exposures that may have
contributed. As the investigation continued it was shown that the afflicted passengers
and crew predominantly consumed food from the ship’s buffet. Environmental factors
then become incredibly important as it is likely that the illness was spread due to poor
food handling practices and a lack of sanitization of cooking services. The handling and
storage practices of the food items should be closely examined to determine if it is
potentially related.
Actions to Take
When an outbreak occurs, the spread must be quickly mitigated. Several
immediate actions can be taken to control the spread. The main action is the immediate
Cruise Ship Analysis
isolation of individuals who are confirmed to be infected. If an individual is exhibiting
symptoms, they should be quarantined in designated areas to minimize contact with
otherwise healthy individuals. This alone will quickly decrease the spread of the
outbreak to the rest of the passengers and crew. Once the affected individuals are
separated from the unaffected individuals, hygiene must be brought to attention. More
specifically strict hygiene practices should be enforced among passengers and crew,
especially in regard to hand washing.3 While hand washing is the best option to prevent
the spread of germs, hand sanitizing stations should also be available throughout the
ship for times when a sink and soap are not readily available. Information should be
handed out regarding the outbreak in a careful manner to prevent mass panic. This can
be done through ship announcements and or posters especially to provide information
regarding preventative measures. If available, in-person sessions can be implemented
to educate passengers and crew on proper hand hygiene and sanitation. The BRAT
(Bananas, Rice, Apple Sauce, Tea, and Toast) diet can then be implemented for those
with the illness she tried to prevent in malnourishment and dehydration.4 Finally, all
buffet and self-service food options should be suspended in order to prevent potential
contamination of the food items. The food should then be handed out as prepackaged
meals that are prepared and handled by unaffected crew members. Following these
immediate actions, an investigation can begin into the initial outbreak of the illness
through interviews with those affected and by creating detailed food diaries and
consumption patterns to identify specific food items associated with the outbreak.4 The
food handling practices should then be inspected as well as sanitation practices and
hygiene protocols on the ship to determine the potential cause of the spread. Water
Cruise Ship Analysis
should be tested for sources of contamination as well as any other environmental
factors that may contribute to the outbreak. In order to prevent more cases from
showing up continuous surveillance should be implemented as well as monitoring
passengers and crew for any other signs of illness even after recovery to prevent
secondary outbreaks. Sanitization practices should be enhanced with all areas of the
ship being rigorously cleaned regularly.
Educational Program
The primary goal of an educational program is to equip food handlers with the
knowledge and skills necessary to prevent and manage outbreaks of foodborne
illnesses. By emphasizing best practices, hygiene, and proactive measures, the
program aims to create a safer food-handling environment and reduce the risk of
outbreaks. The educational program is very multifaceted yet simple at the same time.
Start with an introduction to food safety. In order to prevent outbreaks, one must truly
understand the importance of food safety. Going over an overview of common
foodborne illnesses and their impact on public health helps one realize the importance
of handling food in a safe manner, especially when it is being given to a consumer.
Personal hygiene like proper hand washing techniques and frequency and the use of
gloves and personal protective equipment play a large role in the prevention of
foodborne illnesses. One must also implement A guideline for maintaining personal
cleanliness when working with food. Safe methods for food preparation, including
cutting, chopping, and handling raw ingredients are of utmost importance as cross-
contamination can severely increase the chances of a foodborne illness occurring.
Cruise Ship Analysis
Cleaning and sanitization are also important for utensils cooking surfaces and
equipment as well as the selection of appropriate cleaning agents.5 While it is not
always 100% foolproof it is always best to have safe food sources. Food should always
come from a reputable supplier and should be inspected and, if necessary, rejected
based on its quality. In the case that all these things are implemented and there are still
symptoms popping up emergency procedures should be in place in order to prevent the
spread.6 All incidents of illness or contamination must be immediately reported to
supervisors and health authorities. This education plan can be delivered in several
different ways. The most common are online training modules and hands-on training
sessions. Online training modules are simple because a video can be watched, and a
quiz can then be assessed to test knowledge. Hands-on training sessions offer practical
real-world scenarios for a participant to apply the skills learned. Assessments should be
regularly conducted to measure understanding of key concepts and with successful
completion of the program, certificates can be handed out as proof of completion.
Conclusion
Ultimately, the outbreak of illness aboard the Warped Imagination necessitates
immediate action to prevent further escalation by addressing the root cause. The
statistical calculations show a significant association between watermelon consumption
and the onset of illness. An education program is incredibly important in the prevention
of future potential outbreaks of foodborne illness.
Cruise Ship Analysis
Resources
1. Analyzing and Interpreting Data | Epidemic Intelligence Service | CDC. Published
September 24, 2019. Accessed March 3, 2024. https://www.cdc.gov/eis/field-epi-
manual/chapters/analyze-Interpret-Data.html
2. Nutrition C for FS and A. Outbreak Investigation of Salmonella Carrau: Pre-cut
Melons (April 2019). FDA. Published online February 26, 2024. Accessed March 3,
2024. https://www.fda.gov/food/outbreaks-foodborne-illness/outbreak-investigation-
salmonella-carrau-pre-cut-melons-april-2019
3. Cleanliness Helps Prevent Foodborne Illness | Food Safety and Inspection Service.
Accessed February 21, 2024. http://www.fsis.usda.gov/food-safety/safe-food-
handling-and-preparation/food-safety-basics/cleanliness-helps-prevent
4. Illness Prevention Resources | VSP | CDC. Published August 14, 2023. Accessed
March 4, 2024. https://www.cdc.gov/nceh/vsp/healthy.htm
5. CDC. How to Prevent Food Poisoning. Centers for Disease Control and Prevention.
Published January 24, 2023. Accessed March 4, 2024.
https://www.cdc.gov/foodsafety/prevention.html
6. Biggerstaff G. Improving Response to Foodborne Disease Outbreaks in the United
States: Findings of the Foodborne Disease Centers for Outbreak Response
Enhancement (FoodCORE), 2010–2012. J Public Health Manag Pract JPHMP.
2015;21(4):E18-E26. doi:10.1097/PHH.0000000000000115
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