Case Study: Cruise Ship Analysis Assignment Instructions
Overview
A case study is an in-depth investigation of a group, event, or community. For this assignment, students will be asked to review the cruise ship outbreak information, analyze the data, determine attack rates, and perform the statistical calculations necessary to determine a likely source of the outbreak. In addition, students will be asked to develop a plan to stop the outbreak and an educational program for food handlers to assist them in outbreak prevention. Completing this analysis will grant students to the opportunity to utilize critical thinking skills. In addition, students will be able to apply their knowledge of epidemiology and the outbreak investigative process.
Instructions
You will assume the role of the investigator for the following foodborne illness outbreak. You should ensure that all practices and recommendations are in accordance with the regulations of the governing agency. The case study analysis should include the following components: Comprehensive Analysis of the Data, Statistical Calculations that demonstrate an association with disease and determine the likely source of the outbreak (Specifically focus on the food specific attack rate.), Identification of Probable Source of the outbreak, Actions to Stop the outbreak, and the Educational Program for Food Handlers that highlights outbreak prevention. The required length of this case study is 8 double-spaced pages. The case study should include a title page and reference page. 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 guide.
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.
TABLE 1
onboard food consumption by index case
foods eaten
day 1
day 2
day 3
day 4
day 5
coffee
yes
yes
no
no
no
hot tea
no
no
yes
yes
yes
iced tea
no
no
yes
yes
yes
fountain drink
no
no
yes
yes
yes
ice
yes
yes
yes
yes
yes
watermelon
yes
yes
no
no
no
pineapple
yes
yes
no
no
no
cantaloupe
yes
yes
no
no
no
grapefruit
yes
yes
no
no
no
passion fruit
yes
yes
no
no
no
kiwi
yes
yes
no
no
no
papaya
yes
yes
no
no
no
banana
no
yes
yes
yes
yes
hamburger
yes
yes
yes
no
no
apple juice
yes
yes
no
no
no
prime rib
yes
no
no
no
no
Hawaiian ham
yes
no
no
no
no
green beans
yes
no
no
no
no
carrots
yes
no
no
no
no
creamed corn
yes
yes
no
no
no
broccoli
yes
no
no
no
no
tossed salad
yes
no
no
no
no
white rice
no
yes
yes
yes
yes
boiled potato
yes
no
no
no
no
cole slaw
yes
no
no
no
no
tomato slices
yes
yes
no
no
no
yogurt
no
yes
no
no
no
white bread
yes
no
no
no
no
apple sauce
no
yes
yes
yes
no
ice cream
yes
no
no
no
no
apple pie
yes
no
no
no
no
cheese cake
yes
no
no
no
no
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.
Table 2
onset of cases aboard cruise ship
day 1
day 2
day 3
day 4
day 5
new passenger cases
0
1
0
7
59
new crew cases
0
0
0
3
0
total new cases
0
1
0
10
59
total cumulative cases
0
1
1
11
70
non ill
3700
3699
3699
3689
3630
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.
TABLE 3: Food Consumption from Buffet Aboard Warped Imagination
afflicted passengers and crew
non-afflicted passengers and crew
foods eaten
day 1
day 2
day 3
day 4
day 5
day 1
day 2
day 3
day 4
day 5
bacon
43***
37***
34***
10
0
3000
2763
2879
2556
2865
sausage
24
12
0
12
0
1287
1534
1302
698
779
fried ham
12
17
12
7
0
615
863
827
793
654
pancakes
28
63
27
24
0
1377
3312
1743
1752
1297
French toast
34
12
26
18
0
2300
1389
1476
1576
1681
scrambled eggs
47***
43***
39***
37
0
2548
2334
2089
2192
2212
cold cereal
15
15
12
10
0
800
778
731
803
768
skim milk
66
66
66
57
0
3478
3478
3478
3478
3478
whole milk
3
3
3
0
0
175
175
175
175
175
coffee
70***
70***
69***
59**
0
3497
3512
3612
3597
3581
hot tea
40
40
41
47***
70***
2069
2109
2211
2075
2075
iced tea
40
40
41
47
70***
2081
1056
2112
2333
2100
fountain drink
49***
53***
54***
63***
61***
2217
2749
2757
2566
2239
ice
70***
70***
70***
70***
70***
3630
3618
3624
3630
3630
oatmeal
1
2
1
1
0
122
103
99
76
61
watermelon
60***
60***
60***
50
0
968
763
428
534
677
pineapple
45*
45
40
30
0
2413
2425
2451
2312
2433
cantaloupe
47***
47***
45***
35
0
1287
1286
1290
1301
1287
grapefruit
12
15*
15
11
0
778
779
783
775
715
passion fruit
30
35
45
43
0
1563
1823
2345
2330
2312
kiwi
30
35
35
35
0
1547
1837
1832
1815
1821
papaya
46
47
44
39
0
2401
2412
2397
2076
2073
banana
50***
53***
59***
49***
70***
2593
2852
3112
3018
2987
apple juice
55
54
49
47*
65**
2853
2853
2597
2540
2543
grapefruit juice
0
0
0
0
0
1238
1227
1199
1328
1213
hamburger
70***
70***
70***
59
0
2567
2312
2214
2237
2412
fried chicken
23
14
12
30
0
1296
769
756
1612
987
prime rib
70***
69
58
43
0
3630
3627
3200
2300
2413
Hawaiian ham
59
53
36
38
0
3085
2714
1869
2078
2217
green beans
68**
60
60
53
0
3530
3121
3108
3123
3119
carrots
63
60
38
41
0
3269
3114
1999
2133
2210
creamed corn
35
38***
34
31
0
1036
667
623
519
543
broccoli
33
45
27
28
0
1813
2334
1554
1563
1567
tossed salad
41
63
40
32
0
2232
3278
3206
2111
2328
white rice
53***
48***
43***
70***
70***
2750
2599
2319
2526
2417
mashed potatoes
69***
67*
65
54
0
3602
3526
3418
3515
3591
boiled potatoes
52*
50
54
36
0
2704
2594
2852
2598
2419
potato salad
43
37*
40
13
0
2333
2071
2075
2140
2167
cole slaw
34
33
33
12
0
1728
1823
1873
1856
1917
tomato slices
70***
70***
69**
59
0
3387
1292
1721
1312
1097
asparagus
33
12
25
0
0
1847
1783
1299
1717
787
yogurt
40
12
18
0
0
2047
1555
1113
1719
1982
leaf lettuce
15
33
39
26
0
863
1888
2077
1350
1613
cheddar cheese
25
25
27
23
0
3312
1543
1397
1192
2109
white bread
35
35
35
35
70***
1763
1918
2019
1815
1772
apple sauce
13
17
14
11***
70***
694
893
771
663
894
ice cream
20
23
24
21
0
1067
1284
1281
1093
1123
apple pie
56*
53*
49*
48
0
2988
2748
2587
2554
2548
chocolate cake
66**
67*
56*
43
0
3423
3478
3005
3397
3414
cheese cake
61
60*
58*
48
0
3400
3200
3010
3111
3093
* indicates food consumed by a sickened crewmember
