**Gastroenteritis at a University in Texas**

STUDENT'S VERSION

+-----------------------------------------------------------------------+
| **Original investigators:** Nicholas A. Daniels,^1^ David A.          |
| Bergmire-Sweat,^2^ Kellogg J. Schwab,^3^ Kate A. Hendricks,^2^ Sudha  |
| Reddy,^1^ Steven M.. Rowe,^1^ Rebecca L. Fankhauser,^1,4^ Stephan S.  |
| Monroe,^1^ Robert L. Atmar,^3^ Roger I. Glass,^1^ Paul S. Mead,^1^    |
| Number range CHAPTERRee A. Calmes-Slovin,^5^ Dana Cotton,^6^ Charlie  |
| Horton,^6^ Sandra G. Ford,^6^ Pam Patterson^6^                        |
|                                                                       |
| ^1^Centers for Disease Control and Prevention, ^2^Texas Department of |
| Health, ^3^Baylor College of Medicine, ^4^Atlanta Veterans            |
| Administration Medical Center, ^5^City of Huntsville, Health          |
| Inspections, ^6^Texas Department of Health, Region 6/5S               |
|                                                                       |
| **Case study and instructor's guide created by:** Jeanette K.         |
| Stehr-Green, MD                                                       |
+-----------------------------------------------------------------------+

> *NOTE: This case study is based on a real-life outbreak investigation
> undertaken in Texas in 1998. Some aspects of the original outbreak and
> investigation have been altered, however, to assist in meeting the
> desired teaching objectives and allow completion of the case study in
> less than 3 hours.*
>
> *Students should be aware that this case study describes and promotes
> one particular approach to foodborne disease outbreak investigation.
> Procedures and policies in outbreak investigations, however, can vary
> from country to country, state to state, and outbreak to outbreak.*
>
> *It is anticipated that the epidemiologist investigating a foodborne
> disease outbreak will work within the framework of an "investigation
> team" which includes persons with expertise in epidemiology,
> microbiology, sanitation, food science, and environmental health. It
> is through the collaborative efforts of this team, with each member
> playing a critical role, that outbreak investigations are successfully
> completed.*
>
> *We invite you to send us your comments about the case study by
> visiting our website at
> [http://www.phppo.cdc.gov/phtn/casestudies]{.underline}. Please
> include the name of the case study with your comments.*

**April 2002**

**U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES**

**Public Health Service**

**Centers for Disease Control and Prevention**

**Atlanta, Georgia 30333**

**STUDENT'S VERSION**

**Gastroenteritis at a University in Texas**

+-----------------------------------------------------------------------+
| **Learning objectives:**                                              |
|                                                                       |
| After completing this case study, the student should be able to:      |
|                                                                       |
| 1.  list categories and examples of questions that should be asked of |
|     key informants who report a suspected outbreak of foodborne       |
|     disease                                                           |
|                                                                       |
| 2.  list four criteria for prioritizing the investigation of          |
|     suspected foodborne disease outbreaks                             |
|                                                                       |
| 3.  list three common pitfalls in the collection of clinical          |
|     specimens for the investigation of suspected foodborne diseases   |
|                                                                       |
| 4.  determine the most efficient epidemiologic study design to test a |
|     hypothesis (including the case definition and the appropriate     |
|     comparison group)                                                 |
|                                                                       |
| 5.  describe the advantages and disadvantages of different forms of   |
|     questionnaire administration (e.g., self-administered, telephone, |
|     in-person)                                                        |
|                                                                       |
| 6.  list key areas of focus in interviewing foodhandlers and          |
|     observing kitchen practices in a foodborne disease outbreak       |
+-----------------------------------------------------------------------+

**PART I - OUTBREAK DETECTION**

On the morning of March 11, the Texas Department of Health (TDH) in
Austin received a telephone call from a student at a university in
south-central Texas. The student reported that he and his roommate, a
fraternity brother, were suffering from nausea, vomiting, and diarrhea.
Both had become ill during the night. The roommate had taken an
over-the-counter medication with some relief of his symptoms. Neither
the student nor his roommate had seen a physician or gone to the
emergency room.

The students believed their illness was due to food they had eaten at a
local pizzeria the previous night. They asked if they should attend
classes and take a biology mid-term exam that was scheduled that
afternoon.

[Question 1:]{.underline} What questions (or types of questions) would
you ask the student?

[Question 2:]{.underline} What would you advise the student about
attending classes that day?

The "Foodborne Illness Complaint Worksheet" (Appendix 1) was completed
based on the call. The student refused to give his name or provide a
telephone number or address at which he or his roommate could be
reached.

[Question 3:]{.underline} Do you think this complaint should be
investigated further?

TDH staff were skeptical of the student's report but felt that a minimal
amount of exploration was necessary. They began by making a few
telephone calls to establish the facts and determine if other persons
were similarly affected. The pizzeria, where the student and his
roommate had eaten, was closed until 11:00 A.M. There was no answer at
the University Student Health Center, so a message was left on its
answering machine.

A call to the emergency room at a local hospital (Hospital A) revealed
that 23 university students had been seen for acute gastroenteritis in
the last 24 hours. In contrast, only three patients had been seen at the
emergency room for similar symptoms from March 5-9, none of whom were
associated with the university.

At 10:30 A.M., the physician from the University Student Health Center
returned the call from TDH and reported that 20 students with vomiting
and diarrhea had been seen the previous day. He believed only 1-2
students typically would have been seen for these symptoms in a week.
The Health Center had not collected stool specimens from any of the ill
students.

[Question 4:]{.underline} Do you think these cases of gastroenteritis
represent an outbreak at the university? Why or why not?

**PART II - INITIAL MICROBIOLOGIC INVESTIGATION**

On the afternoon of March 11, TDH staff visited the emergency room at
Hospital A and reviewed medical records of patients seen at the facility
for vomiting and/or diarrhea since March 5. Based on these records,
symptoms among the 23 students included vomiting (91%), diarrhea (85%),
abdominal cramping (68%), headache (66%), muscle aches (49%), and bloody
diarrhea (5%). Oral temperatures ranged from 98.8°F (37.1°C) to 102.4°F
(39.1°C) (median: 100°F \[37.8°C\]). Complete blood counts, performed on
10 students, showed an increase in white blood cells (median count: 13.7
per cubic mm with 82% polymorphonuclear cells, 6% lymphocytes, and 7%
bands). Stool specimens had been submitted for routine bacterial
pathogens, but no results were available.

[Question 5:]{.underline} List the broad categories of diseases that
must be considered in the differential diagnosis of an outbreak of acute
gastrointestinal illness.

[Question 6:]{.underline} How might you narrow the range of agents
suspected of causing the gastrointestinal illness?

TDH staff asked health care providers from the University Student Health
Center, the Hospital A emergency room, and the emergency departments at
six other hospitals located in the general vicinity to report cases of
vomiting or diarrhea seen since March 5. A TDH staff person was
designated to help the facilities identify and report cases. The health
care providers were also asked to collect stool specimens from any new
cases. Bacterial cultures from patients seen in the emergency rooms were
to be performed at the hospital at which they were collected and
confirmed at the TDH Laboratory. Specimens collected by the Student
Health Center were to be cultured at the TDH Laboratory.

[Question 7:]{.underline} What information should be provided with each
stool specimen submitted to the laboratory? How will the information be
used?

[Question 8:]{.underline} How should specimens be transported from the
University Health Center to the TDH laboratory?

Later that afternoon, preliminary culture results from 17 ill students
became available. The specimens, collected primarily from the emergency
room at Hospital A on March 10, did not identify *Salmonella*,
*Shigella, Campylobacter*, *Vibrio*, *Listeria*, *Yersinia*,
*Escherichia coli* O157:H7, *Bacillus cereus*, or *Staphylococcus
aureus*. Some specimens were positive for fecal leukocytes and fecal
occult blood.

[Question 9:]{.underline} How might you interpret the bacterial culture
results? What questions do these results raise?

**PART III - DESCRIPTIVE EPIDEMIOLOGY AND HYPOTHESIS GENERATION**

By March 12, seventy-five persons with vomiting or diarrhea had been
reported to TDH. All were students who lived on the university campus.
No cases were identified among university faculty or staff or from the
local community. Except for one case, the dates of illness onset were
March 9-12. (Figure 1) The median age of patients was 19 years (range:
18-22 years), 69% were freshman, and 62% were female.

Figure 1. Onset of gastroenteritis among students, University X, Texas,
March 1998. (N=72) (Date of onset was not known for three ill students.)

![](media/image1.png){width="5.986111111111111in"
height="4.097222222222222in"}

TDH staff met with the Student Health Center physician and nurse, and
several university administrators including the Provost. City health
department staff participated in the meeting.

[Question 10:]{.underline} What topics would you include in discussions
with university officials?

TDH and City Health Department staff gathered the following information:

> The university is located in a small Texas town with a population of
> 27,354. For the spring semester, the university had an enrollment of
> approximately 12,000 students; 2,386 students live on campus at one of
> the 36 residential halls scattered across the 200+ acres of the main
> campus. About 75% of the students are Texas residents.
>
> The university uses municipal water and sewage services. There have
> been no breaks or work on water or sewage lines in the past year.
> There has been no recent road work or digging around campus.
>
> The campus dining service includes two cafeterias managed by the same
> company and about half a dozen fast food establishments; about 2,000
> students belong to the university meal plan which is limited to
> persons living on campus. Most on-campus students dine at the main
> cafeteria which serves hot entrees, as well as items from the grill,
> deli bar, and a salad bar. A second smaller cafeteria on campus offers
> menu selections with a per item cost and is also accessible to meal
> plan members. In contrast to the main cafeteria, the smaller cafeteria
> tends to be used by students who live off campus and university staff.
> The smaller cafeteria also offers hot entrees, grilled foods, and a
> salad bar, but has no deli bar.
>
> Spring break is to begin on March 13 at which time all dining services
> will cease until March 23. Although many students will leave town
> during the break, it is anticipated that about a quarter of those
> living on campus will remain.

Hypothesis generating interviews were undertaken with seven of the
earliest cases reported by the emergency rooms and the Student Health
Center; all of the cases had onset of illness on March 10. Four were
male and three were female; all but one was a freshman. Two students
were psychology majors; one each was majoring in English and animal
husbandry. Three students were undecided about their major.

The students were from five different residential halls and all reported
eating most of their meals at the university's main cafeteria. During
the past week, all but one student had eaten food from the deli bar; two
had eaten food from the salad bar, and three from the grill. Seven-day
food histories revealed no particular food item that was common to all
or most of the students.

Except for the psychology majors, none of the other students shared any
classes; only one student had a roommate with a similar illness. Five
students belonged to a sorority or a fraternity. Three students had
attended an all school mixer on March 6, the Friday before the outbreak
began; two students went to an all night science fiction film festival
at one of the dorms on March 7. Students reported attendance at no other
special events; most had been studying for midterm exams for most of the
weekend.

[Question 11:]{.underline} Using information available to you at this
point, state your leading hypothesis(es) on the pathogen, mode of
transmission, source of the outbreak, and period of interest.

[Question 12:]{.underline} What actions would you take?

**PART IV - ENVIRONMENTAL INVESTIGATION**

Based on clinical findings, the descriptive epidemiology of early cases,
and hypothesis-generating interviews, investigators hypothesized that
the source of the outbreak was a viral pathogen spread by a food or
beverage served at the main cafeteria at the university between March 5
and 10. As a result, TDH environmental sanitarians inspected the main
cafeteria and interviewed staff on March 12.

Thirty-one staff members were employed at the cafeteria of whom 24 (77%)
were foodhandlers. Except for one employee who worked at the deli bar
and declined to be interviewed, all dining service personnel were
interviewed.

[Question 13:]{.underline} What key areas should be explored during
interviews with the cafeteria foodhandlers?

Cafeteria staff were questioned about their responsibilities in the
cafeteria such as the foods they handled, which meals they served, and
where they usually worked (e.g., deli bar, grill). They were also asked
about use of gloves, handwashing practices, their work schedule during
the week before the outbreak, and if they had been ill at that time.

In the cafeteria, the deli bar had its own preparation area and
refrigerator. During mealtimes, sandwiches were made to order by a
foodhandler. Each day, newly prepared deli meats, cheeses, and
condiments were added to partially depleted deli bar items from the day
before (i.e., without discarding leftover food items). While the deli
was open for service, sandwich ingredients were not kept refrigerated or
on ice. The deli bar containers were not routinely cleaned. Samples of
leftover food, water, and ice were collected.

None of the foodhandlers interviewed reported being ill in the last two
weeks. Stool cultures were requested from all cafeteria staff.

Before dinner on March 12, the City Health Department closed the deli
bar.

[Question 14:]{.underline} Do you agree with the decision to close the
deli bar? What actions would you take now?

**PART V - DESIGNING AN EPIDEMIOLOGIC STUDY TO TEST THE HYPOTHESIS
(STUDY #1)**

On the evening of March 12, about 36 hours after the initial call to the
health department, TDH staff conducted a matched case-control study
among students at the university. Ill students (reported from emergency
rooms and the Student Health Center) who could be reached at their
dormitory rooms were enrolled as cases. Dormitory roommates who had not
become ill were asked to serve as matched control subjects.
Investigators inquired about meals the students might have eaten during
March 5-10 and where the foods were eaten. All information was collected
over the telephone.

[Question 15:]{.underline} What are the advantages and disadvantages of
undertaking a case-control study instead of a cohort study at this point
in the investigation?

[Question 16:]{.underline} How would you define a case for this study?

Twenty-nine cases and controls were interviewed over the telephone.
Investigators tabulated the most notable results in Table 1.

Table 1. Risk factors for illness, matched case-control study, main
cafeteria, University X, Texas, March 1998.

+---------------+-----------+------------+---------+----------+------+
| Exposure      | Ill       | Well       | Matched | 95%      | p-v  |
|               | exposed/  | exposed/   |         | Co       | alue |
|               |           | Total      | Odds    | nfidence |      |
|               | Total     | well\* (%) | Ra      | Interval |      |
|               | ill\* (%) |            | tio\*\* |          |      |
+---------------+-----------+------------+---------+----------+------+
| Ate at deli   | 11/28     | 1/29 (3)   | 11.0    | 1.6-473  | \<   |
| bar --        | (39)      |            |         |          | 0.01 |
|               |           |            |         |          |      |
| lunch on      |           |            |         |          |      |
| March 9       |           |            |         |          |      |
+---------------+-----------+------------+---------+----------+------+
| Ate at deli   | 7/27 (26) | 2/29 (7)   | 6.0     | 0.73-275 | 0.06 |
| bar --        |           |            |         |          |      |
|               |           |            |         |          |      |
| dinner on     |           |            |         |          |      |
| March 9       |           |            |         |          |      |
+---------------+-----------+------------+---------+----------+------+
| Ate at deli   | 8/29 (28) | 1/28 (4)   | 8.0     | 1.1-354  | 0.02 |
| bar --        |           |            |         |          |      |
|               |           |            |         |          |      |
| lunch on      |           |            |         |          |      |
| March 10      |           |            |         |          |      |
+---------------+-----------+------------+---------+----------+------+
| Ate at deli   | 2/29 (7)  | 2/28 (7)   | 1.0     | 0.01-79  | 0.75 |
| bar - dinner  |           |            |         |          |      |
| on March 10   |           |            |         |          |      |
+---------------+-----------+------------+---------+----------+------+
| Ate at deli   | 15/27     | 3/28 (11)  | 7.0     | 1        | \<   |
| bar --        | (56)      |            |         | .61-63.5 | 0.01 |
|               |           |            |         |          |      |
| lunch or      |           |            |         |          |      |
| dinner on     |           |            |         |          |      |
| March 9 or    |           |            |         |          |      |
| lunch on      |           |            |         |          |      |
| March 10      |           |            |         |          |      |
+---------------+-----------+------------+---------+----------+------+

\*Denominator does not always total to 29 because several subjects could
not remember where they ate the indicated meal.

\*\*The data provided for cases and controls cannot be used to calculate
the matched odds ratio which is based on an analysis of discordant
pairs.

[Question 17A:]{.underline} How do you interpret these data?

[Question 17B:]{.underline} What elements of this case-control study
might affect the validity of the measured association?

Eating at the main cafeteria, in general, was not associated with
illness; however eating from the deli bar during lunch on March 9 or
March 10 was significantly associated with illness. Because such a small
number of controls ate at the deli bar, individual food items from the
deli bar could not be examined.

**PART VI - DESIGNING AN EPIDEMIOLOGIC STUDY TO REFINE THE HYPOTHESIS
(STUDY #2)**

By March 13, one hundred and twenty-five persons with vomiting or
diarrhea had been reported to TDH. TDH invited staff from the Centers
for Disease Control and Prevention (CDC) to participate in the ongoing
investigation. CDC staff suggested submission of fresh stool specimens
from ill students for viral studies including reverse
transcriptase-polymerase chain reaction (RT-PCR). TDH and CDC staff
decided to undertake an unmatched case-control study to further explore
the source of the outbreak.

[Question 18:]{.underline} Who should be enrolled as subjects for this
study?

The case-control study was undertaken among students who ate at the main
cafeteria. A case was defined as vomiting or diarrhea (3 loose bowel
movements during a 24-hour period) with onset on or after March 5, 1998,
in a student who was a member of the university meal plan. Cases were
selected from those reported to TDH by one of the local emergency rooms
or the Student Health Center. Controls were students enrolled in the
university meal plan who did not have nausea, vomiting, or diarrhea
since March 5.

Forty cases were randomly selected from the 125 reported through March
13. One hundred and sixty controls were randomly selected from the
university meal plan database.

[Question 19:]{.underline} Investigators considered collecting
information for the case-control study through face-to-face interviews,
telephone interviews, or self-administered questionnaires. What are the
advantages and disadvantages of each method of data collection? Which
method would you recommend given the circumstances around the outbreak?

The investigators administered the study questionnaire by telephone from
March 15-23. Students selected for participation were called at their
dormitory room or their home telephone number as recorded in university
records. If the student was not present at either location but
information on his/her whereabouts was available, additional phone calls
were made to contact the student. Students not reached during spring
break were interviewed on their return to the university.

Thirty-six cases and 144 controls were contacted. Cases included in the
study were similar to all cases with respect to gender, age, and year in
college. Their dates of onset of illness had a distribution similar to
that seen in Figure 1.

Results from the unmatched case-control study were tabulated by TDH and
CDC epidemiologists. Only persons who ate at the main cafeteria for the
specified period were included in the meal-specific analyses. (Table 2)

Table 2. Risk factors for illness among persons eating at the main
cafeteria, unmatched case-control study, University X, Texas, March
9-10, 1998.

+----------------+-------------+--------------+------------+----------+
| Exposure       | Ill         | Well         | Measure of | p-value  |
|                | exposed/    | exposed/     | a          |          |
|                |             | Total well   | ssociation |          |
|                | Total ill   |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at salad   | 9/30        | 36/100       |            |          |
| bar - lunch    |             |              |            |          |
| March 9        |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at salad   | 5/18        | 15/59        |            |          |
| bar - dinner   |             |              |            |          |
| March 9        |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at salad   | 6/28        | 23/96        |            |          |
| bar - lunch    |             |              |            |          |
| March 10       |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at salad   | 6/15        | 12/44        |            |          |
| bar - dinner   |             |              |            |          |
| March 10       |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at salad   | 13/19       | 49/69        |            |          |
| bar\*          |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at deli    | 18/30       | 12/101       |            |          |
| bar -          |             |              |            |          |
|                |             |              |            |          |
| lunch March 9  |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at deli    | 7/18        | 5/61         |            |          |
| bar -          |             |              |            |          |
|                |             |              |            |          |
| dinner March 9 |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at deli    | 13/29       | 12/96        |            |          |
| bar -          |             |              |            |          |
|                |             |              |            |          |
| lunch March 10 |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at deli    | 4/16        | 4/44         |            |          |
| bar -          |             |              |            |          |
|                |             |              |            |          |
| dinner March   |             |              |            |          |
| 10             |             |              |            |          |
+----------------+-------------+--------------+------------+----------+
| Ate at deli    | 28/36       | 20/116       |            |          |
| bar\*          |             |              |            |          |
+----------------+-------------+--------------+------------+----------+

\*for lunch or dinner March 9 or lunch March 10

[Question 20:]{.underline} Calculate the appropriate measure of
association for these exposures. Interpret the results.

To identify the specific item(s) at the deli bar causing the outbreak,
investigators reanalyzed study data from only cases and controls who ate
at the deli bar during March 9-10. (Table 3)

Table 3. Food items eaten by students who ate at deli bar during
implicated meals, unmatched case-control study, University X, Texas,
March 9-10, 1998.\*

+------------+----------+------------+---------+-------------+-------+
| Exposure   | Ill      | Well       | Odds    | 95%         | p-    |
|            | exposed/ | exposed/   | Ratio   | Confidence  | value |
|            |          | Total well |         | Interval    |       |
|            | Total    | (%)        |         |             |       |
|            | ill (%)  |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| American   | 13/28    | 4/20 (20)  | 3.4     | 0.80-17.5   | 0.06  |
| cheese     | (46)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Swiss      | 8/28     | 8/20 (40)  | 0.61    | 0.15-2.4    | 0.30  |
| cheese     | (29)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Ham        | 11/28    | 6/20 (30)  | 1.5     | 0.38-6.3    | 0.36  |
|            | (39)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Turkey     | 15/28    | 11/20 (55) | 0.95    | 0.26-3.5    | 0.57  |
|            | (54)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Shredded   | 13/28    | 10/20 (50) | 0.87    | 0.24-3.2    | 0.52  |
| lettuce    | (46)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Tomato     | 7/28     | 6/20 (30)  | 0.78    | 0.18-3.5    | 0.50  |
|            | (25)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Pickles    | 7/28     | 7/20 (35)  | 0.63    | 0.15-2.6    | 0.63  |
|            | (25)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Mayonnaise | 20/28    | 9/20 (45)  | 3.1     | 0.78-12.4   | 0.06  |
|            | (71)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+
| Mustard    | 10/28    | 9/20 (45)  | 0.68    | 0.18-2.6    | 0.52  |
|            | (36)     |            |         |             |       |
+------------+----------+------------+---------+-------------+-------+

\*includes lunch and dinner on March 9 and lunch on March 10

[Question 21:]{.underline} Interpret the results in Table 3.

**PART VII - ADDITIONAL INVESTIGATIONS**

Water and ice samples obtained from the cafeteria on March 12 were
negative for fecal coliforms. Stool cultures and rectal swabs from the
23 foodhandlers were negative for bacteria.

The staff member who initially refused to be interviewed worked
primarily at the deli bar. When she finally agreed to be interviewed on
March 23, she reported slicing ham on March 9, for use at the deli bar
during lunch and dinner that day, and lunch the following day. She also
prepared and served sandwiches for these same meals. She reported that
she had worn gloves while slicing the ham and while serving sandwiches
at the deli bar. She denied any gastrointestinal illness during the
outbreak period but reported that her infant had been sick with watery
diarrhea since March 7, two days before she prepared items for the
implicated meals. Because the foodhandler wore gloves during food
preparation and serving, she did not feel that handwashing was an
important activity.

Of the 18 fresh stool specimens sent on ill students to CDC, 9 (50%) had
evidence of Norwalk-like virus (NLV) by RT-PCR. Of the four deli foods
available from the implicated meals, only the ham sample, from March 9,
was positive by RT-PCR for the presence of NLV RNA. NLV was also
detected by RT-PCR in a stool sample from the ill infant of the
foodhandler who prepared the deli sandwiches on March 9. The sequence of
the amplified product was identical to those products from the ill
students and the deli ham.

[Question 22:]{.underline} Do you think the evidence implicates the
foodhandler as the source of the outbreak? Explain.

**PART VIII - CONTROL**

Spring break at the university ended on March 23. The chief of the
campus food service called TDH to find out what must be done to reopen
the deli bar.

[Question 23:]{.underline} Which of the following actions would you
recommend? What are the pros and cons of each?

A\) throw away all leftover deli bar foods and ingredients

B)  clean and disinfect all equipment and surfaces in the deli bar

C)  require all foodhandlers to submit a stool specimen before allowing
    them to return to work

D)  educate foodhandlers on proper foodhandling procedures including
    handwashing and appropriate hot-holding and cold-holding
    temperatures

E)  develop a sick foodhandlers policy

[Question 24:]{.underline} Who might you consult in developing
actions/policies for the campus food service to prevent a recurrence of
this problem in the future? Why?

######## APPENDIX 1

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<col style="width: 15%" />
<col style="width: 5%" />
<col style="width: 2%" />
<col style="width: 19%" />
<col style="width: 9%" />
<col style="width: 1%" />
<col style="width: 5%" />
<col style="width: 13%" />
<col style="width: 3%" />
<col style="width: 20%" />
</colgroup>
<tbody>
<tr class="odd">
<td colspan="11"><h1 id="state-department-of-health">State Department of
Health</h1>
<h2 id="foodborne-illness-complaint-worksheet">FOODBORNE ILLNESS
COMPLAINT WORKSHEET</h2></td>
</tr>
<tr class="even">
<td colspan="3"><p id="section" class="heading"></p>
<p id="section-1" class="heading"></p>
<p id="date-031197" class="heading">Date: <u>03/11/97</u></p>
<p>#: <u>97-076</u></p></td>
<td colspan="5"></td>
<td colspan="3"></td>
</tr>
<tr class="odd">
<td colspan="11"><h3 id="person-completing-information"><strong>PERSON
COMPLETING INFORMATION</strong></h3>
<p><strong>Name:</strong> <u>Xavier Onassis</u> : (512)
<u>555-1234</u></p>
<p><strong>Affiliation:</strong>  Local BOH <em>(town)</em>:
______________  State DPH <em>(division)</em>: <u>Epi</u> 
Other:_____________</p></td>
</tr>
<tr class="even">
<td colspan="11"><h3
id="reportercomplainant"><strong>REPORTER/COMPLAINANT</strong></h3>
<p><strong>Name:</strong> <u>Refused to provide</u> <strong>:</strong>
( ) _______ - ___________</p>
<p><strong>Affiliation:</strong>  Consumer
<strong><em><u>specify:</u></em> →</strong></p>
<p> Laboratory division,
____________________________________________________</p>
<p> Local BOH <em>facility,</em></p>
<p> Medical Provider address,
____________________________________________________</p>
<p> State DPH <em>town, etc.</em></p>
<p> Other ____________________________________________________</p></td>
</tr>
<tr class="odd">
<td colspan="11"><h3 id="illness-information"><strong>ILLNESS
INFORMATION</strong></h3>
<p><strong># Persons ill: 2</strong></p>
<p><strong>Symptoms:</strong> <em>(mark if reported <strong><u>for
anyone</u></strong>)<strong>:</strong></em></p>
<p> Diarrhea (both)  Vomiting (both)  Nausea (both)  Abdominal
cramps</p>
<p> Fever (only one)  Bloody stool  Headache (only one)  Muscle
aches</p>
<p> Chills  Loss of appetite  Fatigue (both)  Dizziness</p>
<p> Burning in mouth  Other symptoms: <u>None </u></p>
<p><strong>Onset: →</strong> Earliest Date: <u>03/10/97</u> Time:
<u>11:30</u> AM PM</p>
<p>Latest <strong>(if &gt; 2 ill)</strong> Date: <u>03/11/97</u> Time:
<u>2:30</u> AM PM</p>
<p><strong>Duration:</strong>  Less than 24 Hours  24-48 Hours  More
than 48 Hours  Ongoing  Unknown</p>
<p><strong>Ill Persons: Age</strong></p>
<p><strong>Name Address/Town</strong>  <strong>(yrs) Occupation Med.
Provider/</strong> </p></td>
</tr>
<tr class="even">
<td><strong>1</strong></td>
<td colspan="3"> same as reporter (above)</td>
<td>University X</td>
<td colspan="2">refused</td>
<td>18</td>
<td>student</td>
<td colspan="2">none</td>
</tr>
<tr class="odd">
<td><strong>2</strong></td>
<td colspan="3">refused</td>
<td>University X</td>
<td colspan="2">refused</td>
<td>19</td>
<td>student</td>
<td colspan="2">none</td>
</tr>
<tr class="even">
<td><strong>3</strong></td>
<td colspan="3"></td>
<td></td>
<td colspan="2"></td>
<td></td>
<td></td>
<td colspan="2"></td>
</tr>
<tr class="odd">
<td><strong>4</strong></td>
<td colspan="3"></td>
<td></td>
<td colspan="2"></td>
<td></td>
<td></td>
<td colspan="2"></td>
</tr>
<tr class="even">
<td colspan="11"><p><strong>Medical attention</strong> received
<strong><em>(<u>by anyone)</u></em>?</strong>  Yes  No  Unknown
<strong>→ <em>If Yes, specify above:</em> ↑</strong></p>
<p><strong>Stool specimens</strong> submitted <strong><em>(<u>by
anyone)</u></em>?</strong>  Yes  No  Unknown <strong>→</strong>
<strong>To SLI <sup>1</sup>?</strong>  Yes  No  Unknown</p>
<p><strong>Medical diagnosis</strong>
reported<strong>?</strong></p></td>
</tr>
<tr class="odd">
<td colspan="11"><h3 id="food-history"><strong>FOOD
HISTORY</strong></h3>
<p><strong>→</strong> Obtain history <strong><u>back 72
hours</u></strong> prior to symptoms, <strong>or</strong>, if organism
identified, <strong><u>b/n min and max incubation</u></strong> periods
(see p.2)</p>
<p><strong>→ <u>If &gt; 2 ill</u></strong>, follow above time frame for
<strong><u>common meals (foods) only</u></strong></p>
<p><strong># Restaurant / store where</strong></p>
<p><strong>Date &amp; Time<sup>2</sup> Exp<sup>3</sup> Food(s) consumed
purchased (name, town) Place consumed</strong></p></td>
</tr>
<tr class="even">
<td colspan="2"><p> B</p>
<p>March 8  L</p>
<p> D</p></td>
<td><h3 id="section-2"></h3></td>
<td colspan="3"><h3 id="university-cafeteria">University
cafeteria</h3></td>
<td colspan="4"><h3 id="section-3"></h3></td>
<td><h3 id="same-as-left"><strong> Same <em>(as left)</em></strong>
</h3>
<h3 id="home"><strong> Home</strong></h3>
<p> Other
<em>(specify<strong>)</strong></em><strong>:</strong></p></td>
</tr>
<tr class="odd">
<td colspan="2"><p> B</p>
<p>March 9  L</p>
<p> D</p></td>
<td><h3 id="section-4"></h3></td>
<td colspan="3"><h3 id="university-cafeteria-1">University
cafeteria</h3></td>
<td colspan="4"><h3 id="section-5"></h3></td>
<td><h3 id="same-as-left-1"><strong> Same <em>(as left)</em></strong>
</h3>
<h3 id="home-1"><strong> Home</strong></h3>
<p> Other
<em>(specify<strong>)</strong></em><strong>:</strong></p></td>
</tr>
<tr class="even">
<td colspan="2"><p> B</p>
<p>March 10  L</p>
<p> D</p></td>
<td><h3 id="section-6"></h3></td>
<td colspan="3"><h3 id="anchovy-pizza-and-beer">Anchovy pizza and
beer</h3></td>
<td colspan="4"><h3 id="local-pizzeria">Local pizzeria</h3></td>
<td><h3 id="same-as-left-2"><strong> Same <em>(as left)</em></strong>
</h3>
<h3 id="home-2"><strong> Home</strong></h3>
<p> Other
<em>(specify<strong>)</strong></em><strong>:</strong></p></td>
</tr>
<tr class="odd">
<td colspan="2"><p> B</p>
<p> L</p>
<p> D</p></td>
<td><h3 id="section-7"></h3></td>
<td colspan="3"><h3 id="section-8"></h3></td>
<td colspan="4"><h3 id="section-9"></h3></td>
<td><h3 id="same-as-left-3"><strong> Same <em>(as left)</em></strong>
</h3>
<h3 id="home-3"><strong> Home</strong></h3>
<p> Other
<em>(specify<strong>)</strong></em><strong>:</strong></p></td>
</tr>
<tr class="even">
<td colspan="2"><p> B</p>
<p> L</p>
<p> D</p></td>
<td><h3 id="section-10"></h3></td>
<td colspan="3"><h3 id="section-11"></h3></td>
<td colspan="4"><h3 id="section-12"></h3></td>
<td><h3 id="same-as-left-4"><strong> Same <em>(as left)</em></strong>
</h3>
<h3 id="home-4"><strong> Home</strong></h3>
<p> Other
<em>(specify<strong>)</strong></em><strong>:</strong></p></td>
</tr>
<tr class="odd">
<td colspan="2"><p> B</p>
<p> L</p>
<p> D</p></td>
<td><h3 id="section-13"></h3></td>
<td colspan="3"><h3 id="section-14"></h3></td>
<td colspan="4"><h3 id="section-15"></h3></td>
<td><h3 id="same-as-left-5"><strong> Same <em>(as left)</em></strong>
</h3>
<h3 id="home-5"><strong> Home</strong></h3>
<p> Other
<em>(specify<strong>)</strong></em><strong>:</strong></p></td>
</tr>
<tr class="even">
<td colspan="11"><h3 id="section-16"></h3>
<h3 id="notes"><strong>NOTES</strong></h3>
<p>Student refused to provide food history beyond foods eaten at local
pizzeria. He reported that he and his roommate shared no other meals in
the last 72 hours; they ate separately at the university
cafeteria.</p></td>
</tr>
</tbody>
</table>

+-----------------------+-----------------------+----------------------+
| ###  {#section-17}    |                       |                      |
|                       |                       |                      |
| ### **FOOD TESTING**  |                       |                      |
|                       |                       |                      |
| **Food(s)** available |                       |                      |
| for testing?  Yes   |                       |                      |
| No  Unknown **→**    |                       |                      |
| **Sent to SLI ^1^?**  |                       |                      |
|  Yes  No  Unknown  |                       |                      |
|                       |                       |                      |
| → ***If Yes,          |                       |                      |
| specify** food(s) &   |                       |                      |
| sources*:             |                       |                      |
+-----------------------+-----------------------+----------------------+
| ###  {#section-18}    |                       |                      |
|                       |                       |                      |
| **Product and         |                       |                      |
| Manufacturer          |                       |                      |
| Information for       |                       |                      |
| C                     |                       |                      |
| ommercially-Processed |                       |                      |
| Food(s)**             |                       |                      |
|                       |                       |                      |
| Product name:         |                       |                      |
| \_\_\_                |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| Code/lot              |                       |                      |
| #\_                   |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
|                       |                       |                      |
| Expiration date:      |                       |                      |
| \_\_\_\_\_            |                       |                      |
| /\_\_\_\_\_           |                       |                      |
| /\_\_\_\_\_ Package   |                       |                      |
| size/type:            |                       |                      |
| \_\_\_\_\_\_\_\_\_\   |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
|                       |                       |                      |
| Manufacturer:         |                       |                      |
| \_\_\_                |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| \_\_\_\_\_\_\_\_\_\_\ |                       |                      |
| _\_\_\_\_\_\_\_\_\_\_ |                       |                      |
| : ( ) \_\_\_\_\_\_ - |                       |                      |
| \_\_\_\_\_\_\_\_\_\_  |                       |                      |
|                       |                       |                      |
| Address:              |                       |                      |
+-----------------------+-----------------------+----------------------+
| ###  {#section-19}    |                       |                      |
|                       |                       |                      |
| ### **I               |                       |                      |
| ncubation Periods for |                       |                      |
|  Selected Organisms** |                       |                      |
|                       |                       |                      |
| ######  **Min         |                       |                      |
| Max Min Max Min Max** |                       |                      |
+-----------------------+-----------------------+----------------------+
| ### B. cere           | ### E. coli           | ### Staph.           |
| us (short) 1 hr 6 hrs | O157:H7 3 days 8 days |  aureus 30 min 8 hrs |
+-----------------------+-----------------------+----------------------+
| B. cereus (long) 6    | Hepatitis A 15 days   | Shigella 12 hrs 96   |
| hrs 24 hrs            | 50 days 15-50 days    | hrs                  |
+-----------------------+-----------------------+----------------------+
| Campylobacter 1 day   | Salmonella            | Vibrio cholerae few  |
| 10 days               | (non-typhi) 6 hrs 72  | hrs 5 days           |
|                       | hrs 12-36 hrs         |                      |
+-----------------------+-----------------------+----------------------+
| Cyclospora 1 day 14   | Salmonella typhi 1 wk | Viral GI 12 hrs 48   |
| days 6-8 days         | 3 wks 1-3 weeks       | hrs                  |
+-----------------------+-----------------------+----------------------+
| C. perfringens 6 hrs  | Shellfish poisoning   | Yersinia 3 days 7    |
| 24 hrs 6-24 hrs       | minutes few hrs \<1   | days                 |
|                       | hr                    |                      |
+-----------------------+-----------------------+----------------------+

**1** State Laboratory Institute

**2** Always record **Time** if possible; otherwise, choose
**B**=breakfast, **L**=lunch, **D**=dinner

**3** Total \# persons (both ill and well) who consumed indicated
food(s)

**APPENDIX 2.** Causative agents for acute enteric illness

INFECTIOUS

[Bacteria]{.underline}

*Aeromonas* (not proven)

*Bacillus cereus*

*Campylobacter*

*Clostridium perfringens*

*Escherichia coli*

Shiga Toxin producing *E. coli* (STEC)

Enterotoxin producing *E. coli* (ETEC)

Enteroinvasive *E. coli* (EIEC)

Enteropathogenic *E. coli* (EPEC)

*Plesiomonas* (not proven)

*Salmonella,* non-typhoid

*Salmonella* Typhi

*Shigella*

*Vibrio*

*Yersinia enterocolitica*

[Viruses]{.underline}

Norwalk and Norwalk-like agents

(caliciviruses)

Rotavirus

Hepatitis A

[Parasites]{.underline}

*Cryptosporidium parvum*

*Cyclospora*

*Entamoeba histolytica*

*Giardia lamblia*

TOXINS

*Bacillus cereus*

*Staphylococcus aureus*

*Clostridium perfringens*

*Clostridium botulinum*

heavy metals (cadmium, copper, zinc, tin)

mushroom toxins

fish and shellfish toxins (scombroid, ciguatera)

insecticides

drugs

boric acid

OTHER

psychogenic

radiation

**APPENDIX 3.** Recommendations for Collection of Stool Specimens for
Laboratory Examination *(from the [Morbidity and Mortality Weekly
Report: Recommendations and Reports]{.underline} 1990;30 \[No. RR-14\])*

Specimen collection is critical in identifying the causative agent in an
outbreak of gastroenteritis. Bacteria, viruses, and parasites each
require different specimens and methods of storage and transport for
optimal diagnosis. When the causative agent is unknown, one should
consider plausible pathogens based on predominant signs and symptoms and
other outbreak information.

[For bacterial pathogens]{.underline}

Rectal swabs or swabs of fresh stools should be placed in refrigerated
Cary-Blair transport medium. If the specimens are likely to be examined
within 48 hours after collection, they can be refrigerated at 4C until
shipping. Specimens should be enclosed in a secure container and placed
in a waterproof bag. Specimens should be packed with ice or frozen
refrigerant packs in an insulated box.

If specimens must be held longer than 48 hours, they should be frozen as
soon as possible after collection. Although storage in an ultra-low
freezer (-70C) is preferable, storage in a home-type freezer (if it is
properly set at -20C) is acceptable for short periods. So that the
specimens remain frozen, they should be shipped on dry ice. Sufficient
dry ice should be used to keep specimens frozen until the laboratory
processes them (i.e., enough dry ice to fill one-third to one-half of
the shipping container). Glass tubes should not be in direct contact
with the dry ice; a layer of paper or other material should be placed
between the tubes and the dry ice. To prevent excess exposure to carbon
dioxide (from the dry ice), screw caps should be tightened and sealed
with electrical tape or specimens should be sealed in a plastic bag
within the container of dry ice.

[For viral pathogens]{.underline}

Collect as large a quantity of diarrheal stool as can be obtained (at
least 10 cc). Place in a leak-proof, clean, dry container, and
refrigerate immediately at 4C. DO NOT FREEZE SPECIMENS IF ELECTRON
MICROSCOPY EXAMINATION IS ANTICIPATED. The use of rectal swabs to detect
viral causes of gastroenteritis is discouraged because the sensitivity
of detection compared to bulk stool is suspected to be low.

[For parasites]{.underline}

Mix fresh bulk stool specimens thoroughly with each of two
preservatives, 10% formalin and polyvinyl alcohol fixative, at a ratio
of one part of stool to 3 parts of preservative. If there is any delay
in obtaining the preservatives, refrigerate untreated stool specimens at
4C for up to 48 hours. For routine microscopy, DO NOT FREEZE. Once
preserved, the specimens can be stored and transported at room
temperature or refrigerated. Note, it is now possible to do genotyping
on many parasites, but this may require different preservatives. If
parasites are considered a likely etiology, contact a lab that has the
capacity to conduct genetic testing and ask for specific instructions.
Currently recommended preservatives for genetic analysis include
freezing the specimen or preserving it in ethanol or potassium
dichromate.