Case Study 2

Case Study Instructions

Case Study 2

You will assume the role of the investigator for the following foodborne illness case file. You will analyze the data, determine attack rates, and perform the statistical calculations necessary to find and association with disease and determine a likely source of the outbreak. You will then develop a plan to stop the propagation of the outbreak and create an educational program for food handlers to highlight prevention of a similar outbreak in the future. You should ensure that all practices and recommendations are in accordance with any regulations of the governing agency.

The required length of this case study is 8 double-spaced pages. The title page and reference page are not included in the 8-page minimum requirement. You should include a minimum of 5 sources from government publications. You are welcome to use more sources, but at least 5 sources must be from government publications. The formatting should be consistent with the AMA style format. (Hint: graphs and tables included in this case file may be useful).

CASE:

You have just finished your MPH at Liberty University and have taken a position with the Centers for Disease Control and Prevention (CDC) in the Vessel Sanitation Program (VSP). Today, you have been asked to participate in an investigation of the outbreak of a diarrheal illness aboard the cruise ship Warped Imagination bound to 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 arrival in the US; however, on the fifth 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 case load 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 have been 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 case load 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 4 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 the day prior to their departure from Philadelphia. Their only meal the day of the wedding was a catered dinner of chicken and beef barbeque, mashed potatoes, mixed steamed vegetables, a tossed salad, wedding cake, fruit punch and a glass of champagne. The caterer also provided a box of leftovers which the couple snacked on that evening and again just prior to leaving for the airport on the day the cruise began. They consumed only the complimentary Coke and pretzel snacks during their flight between the time they left home and the time when 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 among the first passengers to eat from the buffet on the ship (See Table 1 for her food diary). The woman was feeling a bit of malaise and wanted to retire early. The following day, the couple had a light breakfast of fruit, yogurt, toast and coffee aboard ship just before making the port of call in Jamaica. The woman claims to have had no appetite that morning and while ashore only sipped a bottle of water acquired from the ship. She consumed no food in Ocho Rios. Her husband had a cola and salt fish.

Ten additional cases were diagnosed by the medical staff the fourth day of the voyage and a total of 70 cases was either diagnosed or self-reported by the fifth day (Table 2). 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.

Detailed food diaries during port of calls for each victim are not available; however, only passengers and crew who have consumed food from the ship’s buffet have become ill. Table 3 is a working spreadsheet of foods consumed by the passengers and crew from the buffet while on board the ship comparing afflicted and non-afflicted individuals.