Part 1. Outbreak Description Instructions: Read the following information and answer the questions below. Situation: Monday, February 4, 2004 9am: A local health department (LHD) in Vermont received a call from a local pediatrician reporting an increase in acute gastroenteritis in patients. Common symptoms included nausea, vomiting, diarrhea, and fever. By 9am that day, the physicians office had already spoken with 7 cases or their proxies (ages ranging from 7-months 17 years) reporting the same symptoms Do you think the cases reported by the pediatricians office represent an outbreak? Justify your answer (if not, what are some other explanations?). What is your advice for the local health department at this point? (5 sentences or less) Update: 2pm: The Health Department called the pediatricians office to follow-up. The office stated they had spoken with more parents throughout the day calling to schedule appointments for GI symptoms. 3pm: A concerned mother of one of the cases called the LHD and wanted to know what the health department was doing about this. She suspected that the outbreak originated at the local elementary school because she had spoken with some other parents whose children attended the same school as her child and their children had similar symptoms. 4:30pm: Another physicians office also called reporting they had noticed an increase in patients with the same GI symptoms that day. The nurse calling to report did not have specific information on case count or patient demographics at the time of the phone call, but stated they had collected several stool samples for testing and would call back when results were available. Given this information, do you feel like we are dealing with an outbreak? Justify your answer. What is your advice for the health department at this point? (5 sentences or less) What are some diseases the physician might have ordered tests for? (1 paragraph) What do you recommend the LHD do (or plan to do) while waiting for these results? Part 2. Verifying Diagnosis Status: There is a cluster of acute gastroenteritis (AGE) cases in a county in Vermont. Update: Tuesday, February 5, 2004 3pm: Three of the four stool samples collected came back positive for norovirus. The youngest case, a one-year old boy, had been hospitalized overnight due to dehydration. The Health Department requested contact information for individuals who had been seen for GI symptoms during the past 3 days at local physicians offices and hospitals. What diagnostic tests are available for Norovirus? (bullet list) What are the advantages and disadvantages of these diagnostic testing procedures? (A table with the first column being tests, and the other two columns being + and is suggested) Update: Wednesday, February 6, 2004 9am: Two of the physicians offices called suspecting that the outbreak may be associated with a local swimming pool, as they noted that several cases had mentioned going swimming the weekend prior. How would you interp.

1. Part 1. Outbreak Description
Instructions: Read the following information and answer the questions below.
Situation:
Monday, February 4, 2004
9am: A local health department (LHD) in Vermont received a call from a local pediatrician
reporting an increase in acute gastroenteritis in patients. Common symptoms included nausea,
vomiting, diarrhea, and fever. By 9am that day, the physicians office had already spoken with 7
cases or their proxies (ages ranging from 7-months 17 years) reporting the same symptoms
Do you think the cases reported by the pediatricians office represent an outbreak? Justify
your answer (if not, what are some other explanations?). What is your advice for the local
health department at this point? (5 sentences or less)
Update:
2pm: The Health Department called the pediatricians office to follow-up. The office stated they had
spoken with more parents throughout the day calling to schedule appointments for GI symptoms.
3pm: A concerned mother of one of the cases called the LHD and wanted to know what the health
department was doing about this. She suspected that the outbreak originated at the local
elementary school because she had spoken with some other parents whose children attended the
same school as her child and their children had similar symptoms.
4:30pm: Another physicians office also called reporting they had noticed an increase in patients
with the same GI symptoms that day. The nurse calling to report did not have specific information
on case count or patient demographics at the time of the phone call, but stated they had collected
several stool samples for testing and would call back when results were available.
Given this information, do you feel like we are dealing with an outbreak? Justify your
answer. What is your advice for the health department at this point? (5 sentences or less)
What are some diseases the physician might have ordered tests for? (1 paragraph)
What do you recommend the LHD do (or plan to do) while waiting for these results?
Part 2. Verifying Diagnosis
Status: There is a cluster of acute gastroenteritis (AGE) cases in a county in Vermont.
Update:
Tuesday, February 5, 2004
3pm: Three of the four stool samples collected came back positive for norovirus. The youngest
case, a one-year old boy, had been hospitalized overnight due to dehydration. The Health
Department requested contact information for individuals who had been seen for GI symptoms
during the past 3 days at local physicians offices and hospitals.
What diagnostic tests are available for Norovirus? (bullet list)
What are the advantages and disadvantages of these diagnostic testing procedures? (A
table with the first column being tests, and the other two columns being + and is suggested)
Update:
Wednesday, February 6, 2004
9am: Two of the physicians offices called suspecting that the outbreak may be associated with a
local swimming pool, as they noted that several cases had mentioned going swimming the
weekend prior.

2. How would you interpret these results? Does this confirm that we are dealing with an
outbreak?
Update:
12pm: Local epidemiologists utilize the county-wide syndromic surveillance system to acquire
expected counts of AGE. As more specimen testing results come in, their findings confirm that the
number of cases is more than expected for this time of year in this area.
Status: Based on lab analyses and clinical diagnosis, an outbreak may be underway, and an
investigation should be launched. The CDC case definition listed below is used as a starting point:
Definition of a Norovirus Outbreak:
An outbreak of norovirus is defined as an occurrence of two or more similar illnesses resulting
from a common exposure that is either suspected or laboratory-confirmed to be caused by
norovirus.
At this point, how will you define:
Suspected cases?
Confirmed cases?
Specifically, what piece of information do you need to obtain from case interviews to
confirm that this is an outbreak?
Part 3. Generating Hypothesis
Status: You have verified the norovirus diagnosis and settled on a case definition based on the
CDC model. Next you need to create a line listing.
As epidemiologists begin to create a line listing, they do some research to refresh their
knowledge of norovirus. Describe norovirus in terms of symptoms, incubation period,
transmission, factors, that increase susceptibility/resistance, common of exposure, etc.
(no more than 1 paragraph)
What information is needed to create a line listing? (bullet list)
Update:
Thursday, February 6, 2004-
11am: Investigators start calling the confirmed and probable cases (and parents of minors) and
conduct 36 hypothesis generating interviews.
What types of exposure information would you solicit on a hypothesis generating
questionnaire? Remember to use any information you uncovered in your previous
literature search. (1 page maximum, cite any literature that you use).