Please help yourself to breakfast Please signin on the attendance sheet Please find your seat names listed on table tents Applied Outbreak Investigation Presented by Names and agencies Date and location ID: 632609
Download Presentation The PPT/PDF document "Welcome to Applied Outbreak Investigat..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Welcome to Applied Outbreak Investigation
Please help yourself to breakfast
Please sign-in on the attendance sheet
Please find your seat (names listed on table tents)Slide2
Applied Outbreak Investigation
Presented by
[Names and agencies]
[Date and location]Slide3
Welcome
Housekeeping:
Facilities
Food
BreaksSlide4
IntroductionsName, Agency, Position
Have you ever investigated an enteric disease outbreak?Slide5
ObjectivesAfter completing this training, participants will:
Be able to define what constitutes an outbreak.
Be able to identify when an outbreak investigation is necessary.
Understand
and practice the
basic steps of an outbreak
investigation.
Understand the roles and responsibilities of epidemiology, environmental health, and laboratory in an outbreak investigation.Slide6
Objectives (continued)After completing this training, participants will:
Be
aware of and know how and when to use outbreak resources and tools available to assist local public health agencies
during outbreaks
.
Know how to document and report on outbreak findings.
Be
aware of communication strategies to employ during an outbreak.Slide7
Structure of this training
Interactive training modules
Clicker voting
STEPS
in an outbreak investigation
Not numbered because each outbreak is unique
May not need to do each step in every outbreak
Outbreaks require flexibility
Follow along on paper copy, laminated copy for reference
Outbreak scenario
* = Resources and toolsSlide8
Overview of State/LocalOutbreak DataSlide9
[Insert 5 slides covering]
All outbreaks by mode of transmission
5 yr foodborne outbreak count
Breakdown of pathogens responsible for foodborne outbreaks
Breakdown of how foodborne outbreaks are detected: complaint vs. routine surveillance
Breakdown of foodborne outbreaks by settingSlide10
State InformationSlide11
State InformationSlide12
State InformationSlide13
State InformationSlide14
Establish Existence of an Outbreak*STEPSlide15
What is an Outbreak?Occurrence of more cases of a disease than is expected
in a given area, or among a specific group of people, over a particular period of time.
Foodborne Outbreak (CDC definition): similar illness in 2 or more people after consuming the same food item in the US.Slide16
Primary Goals of Outbreak Investigations
Stop current outbreak as soon as possible by implementing effective control measures
Prevent similar outbreaks in future
Contribute to food safety and public health policy Slide17
Two Main Ways to Detect Outbreaks
Notification/ complaint system
(on the phone)
Pathogen-specific surveillance
(on the computer)
Types of foodborne illnesses detected
All
(any symptoms)
Only selected diseases
(reportable conditions)
Initiating event
Consumer complaint
(“We puked after eating burgers”)
Positive lab results
(stool culture positive)
Linking cases
Common exposures
Same pathogen
Excluding
unrelated cases
Difficult
(no lab tests, many exposures)
Easier
(PFGE match!)
Detection speed
Faster
(time it takes to make a phone call)
Slower
(time it takes to seek care, be tested, be reported…)
Types of outbreaks best detected
Localized; short incubation
(norovirus at an office party)
Widespread; long incubation
(Hepatitis A in a commercial product)Slide18
Jim calls to report an outbreak at McDonald’s. He dined alone, ate 3 Big Macs®, and developed abdominal cramps and explosive diarrhea within 15 minutes of completing his meal. Your health department has not received other complaints about this facility. Is this an outbreak?
Yes
No
I don’t knowSlide19
A school nurse calls on Thursday morning to report that a bunch of kids are out sick today. A few parents mentioned that their kids have “the flu.” Is this an outbreak?
Yes
No
I don’t knowSlide20
A conference organizer calls you from Idaho to report that she hosted an underwater basket-weaving conference in your jurisdiction two weeks ago. She received complaints from 20% of attendees, from multiple states, that they developed gastrointestinal symptoms within 24 hours of returning home. One person saw a doctor and was diagnosed with Salmonella. Is this an outbreak?
Yes
No
I don’t knowSlide21
PrioritizationLimited resources in public healthHigh priority investigations:
Life threatening illness
Population at high risk for complications
Large number of affected persons
Exposure could be on-going
New cases being reported
Political pressure
Anything that could have been caused intentionallySlide22
Who leads the investigation?Generally, local PH agency leads outbreaks when the exposure and/or the majority of ill people reside within their jurisdiction
With assistance from state health departments as needed
State health departments typically lead:
Multistate clusters/outbreaks
Multicounty clusters/outbreaksSlide23
You work at Mountain County Public Health. It is Friday, December 19, at 3:00 pm. You receive a Shiga Toxin-Producing E. coli (STEC) case in your surveillance system which has been confirmed at the state lab as E. coli O157:H7.
You promptly contact the case, a 25 year old male; he reports that he ate the majority of his meals out in the week prior to his illness.
He says his roommate has also had some diarrhea in the last week.Slide24
E. coli O157:H7
Shiga toxin-producing
E. coli
(STEC): pathogenic; different than
E. coli
found in our guts
Symptoms
Diarrhea (often bloody), abdominal pain, sometimes vomiting and fever
Incubation Period
1 – 10 days (avg 3-4)
Duration
Up to 12 days (can shed for longer)
Transmission
Contaminated food/water (especially ground beef, produce); fecal-oral (animal-to-human, human-to-human)
Reservoir
Gut of cattle, deer, elk, goats, other animals
Special Considerations
Low infectious dose; important cause of hemolytic uremic syndrome (HUS) in children; can persist in environmentSlide25
TIMELINE:
DECEMBER 2014
SUN MON TUE WED THU FRI SAT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Initial
STEC case report
20
21
22
23
24
25
26
27
28
29
30
31
Slide26
Is this an Outbreak?
Yes
No
I don’t knowSlide27
On Monday morning, December 22, you receive a phone call from Rita, a resident of Valley County (a county adjacent to you). Rita and members of her Frisbee Golf team have experienced “stomach flu” over the past week.
Over a week ago, during the weekend of December 6-7, they participated in a Frisbee Golf tournament in
Mountain County
. Slide28
TIMELINE:
DECEMBER 2014
SUN MON TUE WED THU FRI SAT
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
Initial
STEC case report
20
21
22
Complaint call
Frisbee Golf Team ill
23
24
25
26
27
28
29
30
31
Slide29
What questions would you ask?Slide30
From your interview with Rita, you learn:
There are 18 adult players on the team.
Team members live in
Mountain, Valley, and Plateau Counties
.
Rita knows that at least 4 have been sick with some sort of GI symptoms since the tournament, but does not know their exact symptoms. Rita has been ill as well.
One ill person is currently hospitalized in
Plateau County
.
While in
Mountain County
, the team dined at Burger Central and Deli Queen on December 7. Slide31
After talking to Rita, you logged the complaint into Mountain County’s *foodborne illness complaint system.
Here’s a copy of the abbreviated complaint log. What are you concerned about?Slide32
TIMELINE:
DECEMBER 2014
SUN MON TUE WED THU FRI SAT
1
2
3
4
5
Initial STEC case ate at Deli Queen
6
7
Frisbee Golf Team ate at Deli Queen
8
9
10
11
12
13
14
15
16
17
18
19
Initial
STEC case report
20
21
22
Complaint call
Frisbee Golf Team ill
23
24
25
26
27
28
29
30
31
Slide33
Is this an Outbreak?
Yes
No
I don’t knowSlide34
You report the outbreak to the state health department and begin your investigation. Slide35
Form a teamSTEPSlide36
Epidemiology
Environment
Laboratory
Three Legged Stool
Administrative Staff
EPR
Leadership
IT
CommunicationSlide37
Investigation TeamIdentify local, regional, and state resources
Size of team depends on etiology, setting, number of affected people, etc.
Some jurisdictions set up “Outbreak Response Teams” ahead of time
Designate a Leader (could be Epi, EH, director, EPR staff, etc.)Slide38
Consider using Incident Command System (ICS)
ICS: a standardized approach to coordinate, manage, and organize incidents and resources
ICS can be used in outbreak investigations, especially larger/protracted investigations
Training resource: North Carolina Center for Public Health Preparedness – “ICS in Action: Using the Incident Command System in Public Health Outbreak Investigations”
http://cphp.sph.unc.edu/trainingpackages/ics_in_action/
*Sample ICS structure on resource websiteSlide39
Sample ICS StructureSlide40
You form your investigation team.*Back at your office, you can use the “Outbreak Team Members” resource on the resource website to create your office’s outbreak team. Slide41
Attempt to identify etiologySTEPSlide42
Etiology is….
Known
Unknown
Detection method
Pathogen-based
surveillance
Complaint-based
surveillance
Symptoms
Interview
patient to learn if symptoms are consistent with etiology.
Collect
specific symptom information and duration of illness
Onset date
Helps determine exposure date using incubation period
If
exposure date is known (ex wedding party), use to calculate incubation period
Lab tests
Review
results from clinical lab, make sure specimen being forwarded to public health lab
Collect stool
for testing
Resources
Pathogen-based
disease reporting system, communicable disease manual, CDC website, *enteric pathogen table
CIFOR symptom
table:
http://www.cifor.us/documents/CIFORGuidelinesAppendices.pdfSlide43
Specimen Testing at State Public Health LabSlide44
Laboratory Supplies
It is helpful to keep supplies on hand at your agency.
Bulk stool containers and biohazard bags do not expire
Accessories: “hats,” spoons, gloves, labels have a long shelf life
Bacterial transport media swabs (Cary Blair, Amies) have short shelf life, so check the expiration date before using
When working with specimens, follow your agency’s biohazard planSlide45
Specimen Testing at CDPHE Lab
In most outbreak situations, CDPHE can support testing specimens at CDPHE lab
Exceptions
: person-to-person outbreaks in LTCFs or child care centers that are consistent with norovirus/viral gastroenteritisSlide46
[State specific lab info]Info on how to get supplies
What testing can be performed
Lab form and how to complete it
Labeling/identification requirements for specimens
Transport/courierSlide47
Completing Lab Paperworkhttps://www.youtube.com/watch?v=ayBXmtWbOr0Slide48
Collecting and Submitting Specimens
https://www.youtube.com/watch?v=BLm4fCyj1CY&feature=youtu.beSlide49
Getting Specimens to the LabHand-delivered
Specimen receiving door (SE corner of building)
Courier [Insert State information]
FedEx or other shipping service
Biohazard sticker and “Diagnostic Specimen UN3373”
Lab hours: [State Lab Hours]Slide50
Interpretation of Stool Specimen Testing
Positive for certain agent
Patient’s illness caused by agent
Patient colonized with agent but illness not caused by agent
Contamination of specimen
Negative for certain agent
Patient’s illness not caused by agent (caused by another agent requiring different testing)
Collected too late in course of illness
Specimen handled improperlySlide51
When talking to Rita on Monday, December 22, she agreed to provide a stool specimen to public health for testing.Using her bulk stool sample, prepare a bacterial culture swab and package for transport.Slide52
Please complete the specimen and testing sections of the lab form. Consider the symptom profile when deciding which tests to select.How would you get the specimen to the state public health lab from YOUR public health agency?Slide53
Define and identify casesSTEPSlide54
Establish a Case DefinitionWhat is a “case”?
Typically contains the following elements:
Clinical information and/or laboratory results.
Characteristics about the people affected (person).
Information about the place of exposure (place).
Time during which the outbreak occurred (time).Slide55
Example Case Definition
A case is defined as an individual experiencing diarrhea (defined as at least three loose stools in a 24-hour period) and dined at “Restaurant X” between January 15 and January 25. Slide56
Case Definitions are Important
Accurately capturing who is and isn’t part of an outbreak
Allows you to describe your outbreak in order to implement appropriate public health action
Reduces bias in your results
They allow you to test hypotheses
Do
NOT
include suspected vehicle of outbreak (i.e., hypothesis you are trying to test)
Slide57
A case is defined as a person who attends or works at “Child Care Center X” who became ill with vomiting and/or diarrhea (defined as at least 3 loose stools in a 24 hour period) whose symptoms lasted less than 72 hours.
What is missing from this child care center outbreak case definition?
Person
Place
Time
Clinical InformationSlide58
A confirmed case is defined as an individual with laboratory confirmed Salmonella Typhimurium between January 15 and January 25.
What is missing from this outbreak case definition?
Person
Place
Time
Clinical InformationSlide59
What is wrong with this case definition?
Ogres are not people
The place is missing
Suspected vehicle is included in case definition
Nothing, this is a good case definition
A case is defined as an ogre living in the swamp near Lord Farquaad’s Kingdom experiencing diarrhea (defined as 3 or more loose stools in 24 hours), with onset after eating cake at Shrek and Fiona’s wedding.Slide60
More on Case DefinitionsYou may have separate definitions for confirmed, probable, and suspect cases.
Case definitions are often changed and refined as more information about the outbreak is gathered.
Usually, your initial case definition does not include any suspected sources of the outbreak
Analyze your data using your case definitions!Slide61
Example Case Definitions Confirmed
: Laboratory –confirmed case of Shigella in a child or staff member at childcare center A with onset since January 29, 2014.
Probable
: A child or staff member at childcare center A with diarrhea (defined as 3 or more loose stools in a 24-hour period) for 72 hours or more, with onset since January 29, 2014.
Suspect
: A child or staff member at childcare center A with gastrointestinal symptoms. Slide62
Case FindingCast a wide net to identify population at risk
Identified cases may be “tip of the iceberg”
Surveillance methods:
Passive Surveillance: Health care providers and laboratories report cases of disease to health department
Active Surveillance: Health department contacts health care providers (or others) requesting information about conditions or diseases to identify possible casesSlide63
Exposure in the general population
Person becomes ill
Person seeks care
Specimen obtained
Laboratory confirmed case
Reported to Health Dept
Lab tests for organism
Pyramid of Reporting
Public health surveillance Slide64
Case Finding Methods
Ask organizer for a list of attendees
Routine notifiable disease surveillance
Email other local public health agencies
National outbreak email list serves/web boards
Reservation lists / credit card sales
Web orders
Contact ERs, local medical offices, labs – health alerts
Other cases—is anyone else ill?
Review complaints received at the health dept
Press release
*Sample health alerts, press releases, letters to schools/childcares
Which of these methods are passive surveillance?Slide65
On Tuesday, December 23, the local hospital calls to say that they have another case of STEC in a 7 year old girl.Upon interviewing her mother, she dined at Deli Queen on Monday, December 8.On Friday, December 26 you receive results from Rita’s stool specimen that was tested at the State Public Health Laboratory – it is positive for STEC O157.Slide66
TIMELINE:
DECEMBER 2014
SUN MON TUE WED THU FRI SAT
1
2
3
4
5
Initial STEC case ate at Deli Queen
6
7
Frisbee Golf Team ate at Deli Queen
8
2
nd
STEC case ate at Deli Queen
9
10
11
12
13
14
15
16
17
18
19
Initial
STEC case report
20
21
22
Complaint call
Frisbee Golf Team ill
23
2
nd
STEC case report
24
25
26
Rita
– stool tests positive for STEC
27
28
29
30
31
Slide67
Create a case definition
Remember to include:
Person
Place
Time
Clinical information Slide68
How do we identify additional cases?Slide69
Describe and orient the data (DESCRIPTIVE EPIDEMIOLOGY)STEPSlide70
Line ListContains basic information about each person suspected to be part of a cluster or outbreak
Allows information about time, person, and place to be organized and reviewed
Best to develop in an electronic format (Excel, Access, Epi Info)
In large outbreaks, designate one person to be in-charge of the line list (full time job)Slide71
Line List Example
Each row represents one person
Each column represents a variable of interest
Can add/take out variables as needed
*Line list templateSlide72
Descriptive Epidemiology Clues
Person-to-person transmission
Clustering in social units
Localized to one part of community
Occurrence of cases in waves
Transmission by public drinking water
Widespread illness
Affecting both sexes and all age groups
Distribution consistent with public water system
Transmission by food
Increased risk among certain groups
Distribution similar to distribution of foodsSlide73
What can your data tell you?
Who is ill?
E. coli
O157 – 2009 – 80 cases – 31 states
Unique vehicle for this pathogen – consuming prepackaged raw cookie doughSlide74
What can your data tell you?
What might be the etiology?
Symptoms
n
%
Diarrhea
51/51
100
Bloody diarrhea
12/44
27
Abdominal pain
40/49
81
Fever
36/48
75
Myalgia
24/47
64
Vomiting
18/48
37
Hospitalized
3/51
6Slide75
What can your data tell you?Slide76
Construct an Epidemic Curve
Title your epi curve
Create your horizontal axis: TIME
Preferably use onset date
Units ¼ to ½ of incubation period work best
Consider adding an incubation period to the x-axis on both sides of the cases
Create your vertical axis: NUMBER OF CASES
Build a histogram using your line list
Note important events (optional)
Interpret your epi curveSlide77
Uses of Epi Curves
Grasp magnitude of outbreak
Clarify outbreak’s timeline
Identify cases that are outliers
Draw inferences about pattern of spread
Point source outbreak
Continuous common source outbreak
Propagated outbreakSlide78
Point Source Outbreak
Exposure to same source over brief time
Cases rise rapidly to a peak and fall off gradually
Majority of cases within one incubation period
Cryptosporidiosis cases, June
one incubation period = 7 daysSlide79
Infections with
Salmonella
Enteritidis by date of onset of illness, January and February.
January
February
Continuous Common
Source Outbreak
Exposure to same source over prolonged time
Epidemic curve rises gradually
May plateau
one incubation period = 2-3 daysSlide80
Propagated Outbreak
Spread from person to person
Series of progressively taller peaks
Peaks one incubation period apart
one incubation period = 10 days
October
November
December
January
Measles cases by date of onset of illness, Aberdeen, South Dakota, October 15 – January 16Slide81
Person-to-Person (propagated)
Point-Source
Continuous Common
Source
What type of outbreak does this Epi Curve demonstrate?Slide82
Person-to-Person (propagated)
Point-Source
Continuous Common Source
What type of outbreak does this Epi Curve demonstrate?Slide83
Person-to-Person (propagated)
Point-Source
Continuous Common Source
What type of outbreak does this Epi Curve demonstrate?Slide84
Let’s Review the Outbreak!
You are investigating an enteric disease outbreak
There are 5 ill people who meet confirmed and probable case definitions
2 identified through public health surveillance
3 are members of the frisbee golf team; illness was discovered through a complaint call
All cases report eating at Deli Queen between December 5
th
and 8
th
Slide85
You have some information on 6 ill people that you put into a line list:Rita3 other team members, one hospitalizedInitial reported case - 25 year old STEC case
Second reported case - 7 year old hospitalized STEC case Slide86
Tabulate and Describe Study DataApply your case definition
Calculate basic descriptive data
% male/female
Median age (range)
Symptom description
% hospitalized
Any deaths
Etc.Slide87
Using the data in the line list, calculate:% male/femaleMedian age (range)Symptom
description (frequency and %)
… this data will populate “Table 1.”Slide88
Table 1. Description of Cases
Median
Range
Age
49
(7-55)
Number
Percent
Sex
Male
2
40%
Female
3
60%
Symptoms
Diarrhea
5
100%
Bloody Diarrhea
5
100%
Abdominal Cramps
5
100%
Vomiting
2
40%
Fever
4
80%
Headache
4
80%
Body Aches
3
60%
Hospitalizations
2
40%
Deaths
0
0Slide89
From this line list, apply your case definition and construct an epi curveSlide90
TIMELINE:
DECEMBER 2014
SUN MON TUE WED THU FRI SAT
1
2
3
4
5
Initial STEC case ate at Deli Queen
6
7
Frisbee Golf Team ate at Deli Queen
8
2
nd
STEC case ate at Deli Queen
9
10
11
12
13
14
15
16
17
18
19
Initial
STEC case report
20
21
22
Complaint call
Frisbee Golf Team ill
23
2
nd
STEC case report
24
25
26
Rita
– stool tests positive for STEC
27
28
29
30
31
Slide91Slide92
Develop hypothesisSTEPSlide93
Developing a Hypothesis
Using available information to make an educated guess about the cause and source of an outbreak
Purpose
To direct immediate control measures
To narrow focus of subsequent studies
To determine the need to involve others in investigation
Undertaken by entire teamSlide94
Elements of a Hypothesis
Includes likely causative agent, people at risk, mode of transmission, vehicle, and period of interest
Example:
“The outbreak is due to a bacterium that was spread during the first week of November by a food commonly consumed by children.”Slide95
Key Sources of InformationBasic information about causative agent
Information on implicated facility or food
Descriptive epidemiology (i.e., describe cases by time, place, and person)
Case interviews (“hypothesis-generating interviews”)Slide96
What is your leading hypothesis?Using the data you have, what is your leading hypothesis?
Includes likely causative agent, people at risk, mode of transmission, vehicle, and period of interest
What are some other possible hypotheses?Slide97
Evaluate hypothesis - EpiSTEPSlide98
Purpose of an Epi StudyTest a hypothesis
Compare ill cases to people who did not become ill to see if commonalities are:
Reflective of population at large?
A chance happening?
Related to an unknown factor?
Two common analytical studies are cohort study and case-control study
*Study Design
HandoutSlide99
Cohort StudyPopulation is well defined
Start with who is
exposed
, then determine who is ill
Examples: church potluck, wedding, school class, jail
Illness
Did not eat food
No illness
Illness
No illness
Ate foodSlide100
Case-Control StudyPopulation is NOT well defined
Start with who is
ill
, then determine who ate food
Identify potential controls
Random or sequential digit dialing
Neighborhood controls
Example: Matching PFGE pattern in different states
Controls
Ate food
Ate food
Did
not eat food
Did not eat food
CasesSlide101
How to choose?Are members of the group easily identifiable?
What is known about the exposure-disease relationship?
What resources do you have?Slide102
A local health department receives reports of gastrointestinal illness from attendees of a polka festival in the local county. Which study design would you use?
Cohort study
Case-control studySlide103
An estimated 1,200 people attended a conference. Food trucks served food during the event, none of which were licensed, and many people became ill. The conference is now over, and most attendees have returned home. Which study design would you use?
Cohort
Case-controlSlide104
A total of 11 people are infected with a matching strain of Salmonella in three states. Which study design would you use?
Cohort
Case-controlSlide105
Several members of a cow share are ill with Campylobacter. Which study design would you use?
Cohort
Case-control Slide106
There is an E. coli O157 outbreak with 9 ill cases in the Denver Metro Area. Which study design would you use?
Cohort
Case-controlSlide107
What type of study would you conduct for this outbreak?Slide108
You decided to do a cohort study with the Frisbee Golf Team. You would then develop a questionnaire based on the Deli Queen menu. Slide109
Develop QuestionnaireFirst, talk to your colleagues at state and local health departments. There is probably another questionnaire or template you can modify. Don’t reinvent the wheel!Slide110
Here is the questionnaire used for this outbreak.Slide111
Questionnaire Components
Introduction
Demographics on respondent
Illness information
Exposure information
Secondary transmission
Conclusion/follow-upSlide112
Questionnaire DatabaseMicrosoft Access, Excel, Epi Info 7
Database should mirror questionnaire to allow for easy data entrySlide113
Example: Epi Info Form
Free
software developed by CDC for the public health community
Performs data:
collection
management
analysis
visualization
Download at:
http://wwwn.cdc.gov/epiinfo/html/downloads.htmSlide114
Questionnaire and Database Tips
Write questions in an unbiased manner
Do not use “leading” or “loaded” questions
Keep each question brief, simple and specific
For every field you create, ask yourself:
What is the intent of this question?
Will people answering the survey understand the question? (avoid jargon, abbreviations, etc.)
What type of answers/data am I looking for?
i.e., numeric, text, date, time, etc.
How will I analyze this data? Slide115
Update your epi curve with this additional information Slide116
It’s stats time!Choose the correct measure of association
Complete 2x2 tables
Use Epi Info to calculate
Interpret the results
*Study Design & Analysis ToolSlide117
1. Choose Measure of Association
Cohort study: calculate relative risks (also called a risk ratio)
Case-Control study: calculate odds ratios
How? Epi Info 7 is a free tool that can do all of thisSlide118
Which measure of association should we calculate?Slide119
Ate food item or exposed
Did not eat food item or not exposed
a
b
c
d
2. Complete 2 x 2 Tables
Cases or Ill
Controls or Well
a = cases who were exposed
b = controls who were exposed
c = cases who were not exposed
d = controls who were not exposedSlide120
*Here’s the new line list that includes some exposure dataWho do we include in cohort analysis?Create 2 x 2 tables for each food item on the line list.Slide121
3. Use Epi Info*Slide122
Together, using Epi Info STAT CALC, let’s calculate relative risks for each food item. Slide123
4. Interpret
Odds
Ratio
Relative
Risk
Interpretation
Close to 1.0
Odds of exposure is similar among
cases and controls
Risk of disease
is similar among exposed and not exposed
Exposure
not associated with illness
Greater than 1.0
Odds of exposure
among cases is higher than among controls
Risk of disease
is higher among exposed than not exposed
Exposure
could be a risk factor for illness
Less
than 1.0
Odds of exposure among cases
is lower than among controls
Risk of disease
is lower among exposed than not exposed
Exposure could be a “protective
factor”
Magnitude
Reflects
strength of association between exposure and illnessSlide124
Let’s interpret our relative risksSlide125
ATE FOOD
DID
NOT EAT
FOOD
FOOD
Ill
Well
Total Who Ate Food
Attack Rate (%)
Ill
Well
Total Who Did Not Eat Food
Attack Rate (%)
Relative Risk
Confidence
Interval
Veggie Sandwich
3
5
8
38%
2
7
9
22%
1.7
(0.4,
7.7)
Turkey Sandwich
2
7
9
22%
3
5
8
38%
0.6
(0.1, 2.3)
Tomato
3
6
9
33%
2
6
8
25%
1.3
(0.3, 6.1)
Lettuce
3
7
10
30%
2
5
7
29%
1.1
(0.2, 4.7)
Sprouts
4
1
5
80%
1
11
12
8%
9.6
(1.3, 65.9)
Food ResultsSlide126
Evaluate hypothesis –Environmental HealthSTEPSlide127
Environmental AssessmentEssential to investigating outbreaks
Onsite investigations should be done as early in the investigation as possible
Multiple visits may be necessary
*Tool: Environmental Assessment QuickTrain
*Tool :
CDC e-Learning on Environmental Assessment
*Tool: Environmental Assessment Quick ReferenceSlide128
Routine Regulatory Inspection
Environmental Assessment
Focus
Common food safety problems
Food safety problems related to suspected food during outbreak period
Timeframe of Interest
Present
Past
Undertaken
Regularly scheduled but often unannounced
In response to a specific problem
Initiated by
Regulatory Agency
Outbreak Investigation Team
Regulatory Authority
State or local environmental health departments
State or local public and/or environmental health departments
Routine Inspection vs.
Environmental AssessmentSlide129
Preparation for Assessment
Epi will communicate:
Causative or suspect agent
Onset of illness among cases
Likely exposure dates/meals/foods
EH will review:
Existing regulatory records
Menus, recipes, product formulations
Facility disease control policies
Epi and EH together will discuss:
History of outbreaks at facility
Reservoirs and previously identified vehicles
Modes of transmission
Likely contributing factorsSlide130
Investigate Suspected Food Item(s)
“When you have a foodborne outbreak,
more than one thing
went wrong.”Slide131
Contributing FactorsContamination
Bare-hand contact by ill person
Contaminated raw product
Survival
Time and temperature abuse
Proliferation and Amplification
Time and temperature abuse
Inadequate processing (acidification, fermentation)Slide132
Generalizations
Causative agent
Common contributing factors
Spore formers and
preformed toxins
Cooling, reheating, hot holding, bare- hand contact, room temperature storage, cold holding
Viral infections
Ill food worker, bare-hand contact, inadequate handwashing, contaminated raw products, contaminated surfaces
Bacterial infections
Ill food worker, bare-hand contact, inadequate handwashing, contaminated raw product, cross-contamination, inadequate cooking
Parasitic infections
Contaminated raw products, source, water, cross-contamination, inadequate cookingSlide133
Look for Ill FoodhandlersInterview persons associated with the facility
All levels (dishwasher
to owner)
Were they sick too?
*Food handler/manager questionnaire templates:
https://www.colorado.gov/pacific/cdphe/outbreak-investigation-guidelines
Collect stool from workers (depending on situation)Slide134
Collect DocumentationCollect pertinent records
Menus
Invoices and delivery logs
Employee schedules
Employee sick policy
Reservation lists
Complaints received by restaurant
If shellfish is involved, shellfish tags
Take photos, especially of documents you cannot takeSlide135
Environmental SamplingWe love having positive food tests!!!!
Collect and hold food and environmental samples if available
However, be aware that:
Food and environmental testing is complicated/expensive
Usually only test when pathogen is known AND there is strong epi evidence implicating a food item
*Environmental Sampling LogSlide136
TracebackLocal public health often starts the traceback process
Gathered information may be shared with state health department and FDA/USDA
*Which federal agency had jurisdiction over which foods?
http://www.fda.gov/downloads/ICECI/Inspections/IOM/ucm127390.pdfSlide137
Traceback Diagram created during
Listeria
outbreak associated with Colorado-grown cantaloupes, 2011Slide138Slide139
Would you collect food and/or environmental samples for testing in this outbreak?If so, what food item(s)?
Would you start traceback activities?Slide140
Which EH actions would be most crucial at this point? Pick two.
Interview foodhandlers
Conduct traceback
Collect menus and receipts
Review preparation for all menu items
Review preparation for suspected items
Review complaint history for Deli QueenSlide141
An Environmental assessment was conducted at Deli Queen on Wednesday, December 24. During the Environmental Assessment, you determine that at least one food handler was ill with diarrhea in the beginning of December. Slide142
EH collected produce items (lettuce, sprouts, tomatoes, onions, cucumbers) along with other items that were statistically associated with illness to submit to the State Laboratory for STEC testing; these items are not likely from the same lots served to the ill persons due to product turnover.The
lab only tested the sprouts
They were negative for STECSlide143
TIMELINE:
DECEMBER 2014
SUN MON TUE WED THU FRI SAT
1
2
3
4
5
Initial STEC case ate at Deli Queen
6
7
Frisbee Golf Team ate at Deli Queen
8
2
nd
STEC case ate at Deli Queen
9
10
11
12
13
14
15
16
17
18
19
Initial
STEC case report
20
21
22
Complaint call
Frisbee Golf Team ill
23
2
nd
STEC case report
24
EH Assessment at Deli Queen
25
26
Rita
– stool tests positive for STEC
27
28
29
30
31
Slide144
Implement control and prevention measuresSTEPSlide145
Control MeasuresImplement as soon as the outbreak is discovered and throughout the course of the investigation
Balance between preventing further disease and protecting credibility/reputation of facility
Guided by evidence from investigation
Do not need to wait for laboratory results
Control measures may change or expand as more is known
*
Guidelines for Control of Enteric PathogensSlide146
ExamplesEducation and Training
Clean and disinfect facility
Exclude from high risk settings and/or duties (food service, health care, childcare)
Tell the public to avoid a food
Cohort ill persons
Temporarily close restaurant, food producer, or facility (or halt new admissions)
Recall food itemsSlide147
Which Control Measures are most important? Choose your top 2 in order.
Exclude ill foodhandlers
Test all foodhandlers at Deli Queen for E. coli
Close the restaurant
Educate all members of Frisbee golf team about E. coli
Instruct ill persons to not work in sensitive occupations while ill
Quarantine all members of Frisbee golf teamSlide148
Communication during and after outbreakSTEPSlide149
CommunicationEffective communication is vital throughout the outbreak investigation
Methods and extent of communication will depend on
Type of outbreak
Size of outbreak
Needs and expectations of your community
Agency policiesSlide150
Internal CommunicationConsider doing daily internal updates early in the investigation
Can be via meetings or update email
Ongoing documentation
Emails
Notes
Timelines
Situation reports
Involve your PIO early in the investigationSlide151
External CommunicationNotify relevant public health partnersNeighboring counties
State health department
Other stakeholders
Press release may be necessary
Are others at risk of being exposed?
Disease prevention/control measures?
Media may be alerted by affected persons
Be prepared to respondSlide152
External CommunicationHealth Alert Network is often useful to inform health care partners
Other methods:
Letters home to parents (schools, child cares)
Fact sheet to affected individuals
Posting signs/warnings
*Samples of press releases and HANS are on your resource websiteSlide153
Closing an outbreakSTEPSlide154
When is it over?Depends on the type of outbreak, transmission route, etiology, etc.
Sometimes 2 incubation periods after the last case’s onset is used as a measure to determine if outbreak is overSlide155
Outbreak Debrief / HOT WASHWhat were our successes?
What were our challenges?
What can we do better next time?
Develop improvement plan based on findings
Include internal and external partners who participated in the outbreak investigation.Slide156
Outbreak ReportIntroduction/Background
Methods
Results
Discussion
Recommendations
Conclusion
Acknowledgements
Supporting documents
*Sample outbreak reports
After Action Reports
Confidential Information Slide157
NORS FormNational Outbreak Reporting System
Timeline for submitting
When to complete NORS form
Video guidance:
https://www.youtube.com/watch?v=3QmNcPvrO3c
Fillable NORS form
http://www.cdc.gov/nors/pdf/NORS_CDC_5213-fillable.pdf
*NORS Guidance documentSlide158
Legal ConsiderationsIncreasingly, outbreaks result in litigation
Outbreak documentation could be subject to the Open Records laws
Emails
Outbreak report
HANS, letters, press releases
Completed questionnaires
Case records
Lab resultsSlide159
Legal Considerations (cont.)Ensure confidential information is redacted
Individual cases can obtain records about their illness
*Guidance on releasing case information
Consult your agency’s policySlide160
A case in the outbreak calls you to let you know that he wants to sue the Deli Queen. How would you handle this?Slide161
Wrapping UpWrite an outbreak report
*Complete NORS FormSlide162
Common Outbreak PitfallsNot investigating because the outbreak “occurred too long ago” or “is over”
Questionnaires not filled out completely
Not creating or applying a case definition
Not interviewing well persons
Not collecting specimens for testing (especially human)
CommunicationSlide163
Any questions?Slide164
Norovirus 101
Special Thanks to:
Amy Woron, Molecular Biologist, TN SPHL
Traci DeSalvo, Epidemiologist, WI DOH
Brian Collins, Director of Env Health, City of Plano, TX
Leslie Barclay, CDC
Julia Wolfe, Orange County, CA
Michele Samarya-Timm, Somerset County, NJSlide165
ObjectivesLearn the basics of norovirusEpidemiology of norovirus Slide166
Have you ever suffered from norovirus?
YES
NO
I don’t know – I’ve blocked those memoriesSlide167
July 2: Two days before the July 4th holiday…..Slide168
Time to shop for all the July 4th essentials!Slide169
Nausea suddenly takes a nasty turn…..Slide170
What are the typical norovirus symptoms?
Sneezing, coughing, headache
Vomiting, diarrhea, nausea, feeling like you are going to die
Fever, skin rash, body aches
Fever, headache, stiff neck, nausea, vomitingSlide171
Sick and embarrassed, she leaves the store immediatelySlide172
How far can vomit travel through the air?
Up to 2 feet
Up to 5 feet
Over 10 feet
Not as far as I can runSlide173
Who (and what) has been or could be exposed?Slide174
What is the infectious dose of norovirus?
<20 viral particles
50-100 viral particles
100-1000 viral particles
> 1000 viral particlesSlide175
How is norovirus transmitted?
Fecal-oral transmission
Vomit-oral transmission
Consuming contaminated food or water
Touching surfaces contaminated with vomit or diarrhea and then touching your mouth
All of the aboveSlide176
Transmission: Highly Contagious!
Very
low infectious dose
(<20
particles)
Virus highly concentrated in
stool/vomit of infected people
1 gram of feces contains ~5 billion viral particles
Communicability:
Most
contagious while
symptomatic
Transmission
documented at least
2
days after
ill person recovers
People
can shed virus for up
to four weeks
after
recovery (possibly longer)Slide177
TransmissionFecal/vomitus
oral
Foodborne
Waterborne
Person-to-person
Fomites / environmental contamination
Norovirus can be recovered on surfaces after 3 – 4 weeks at room temperature!
“Airborne” spread
Aerosolized vomitus can travel
over 10 feet in the air and
settle on environmental surfaces
If you touch these surfaces and
then touch your mouth you can be infectedSlide178
Store Maintenance is called to Clean the MessSlide179
Which of the following is effective at killing norovirus?
Any type of cleanser
Bleach
Ammonia
Hot water from the tapSlide180
Residual Norovirus with Various Cleaning Methods:
100
% of contaminated surfaces still have norovirus after being cleaned with detergent
and water
14
% – 28
% of contaminated surfaces still have norovirus after applying a 5000 ppm bleach solution for 1 to 5 minutes
0
% of contaminated
surfaces
have residual norovirus when cleaned
with detergent and water, then treated with 5000
ppm bleach solution for 1 minute
Source: Barker
et al;
“
Effects of cleaning and disinfection in reducing the spread
of Norovirus contamination via environmental surfaces.”
Journal of Hospital Infection 2004 Sep;58(1):42-29Slide181
July 3: The July 4th party is tomorrow…Slide182
July 4: Party time!Slide183
What is the incubation period for norovirus?
6-12 hours
12-48 hours
3-5 days
> 7 daysSlide184
July 5: Uh oh…several guests aren’t feeling so well….Slide185
Norovirus Basics
Causes viral gastroenteritis:
rarely fatal
Vomiting
Low-grade
fever
Headache
Chills
Incubation period:
12
– 48
hours (avg 30)
Duration of symptoms:
12
– 60
hours (avg 24)
Reservoir:
humans
Treatment:
fluid
replacement
Immunity:
short-lived (viruses evolve)
Diarrhea
(watery)
Abdominal cramps
Nausea
Malaise and body
achesSlide186
Testing – human specimensNorovirus RT-PCR is widely available at commercial labs and is available at most state public health labs.
In outbreak settings, your state lab may cover testing fees or it may be fee-for-service.Slide187
Preventing NorovirusHandwashing, handwashing, handwashing
Wash fruits and vegetables thoroughly
If you are sick, do not prepare food for others
Promptly clean and disinfect surfaces contaminated by feces or vomit
Promptly launder contaminated clothes, towels, linens, etc.Slide188
Norovirus ResourcesNorovirus One Minute Medical School:
http://www.youtube.com/watch?v=HAhuDfD0LfY
CDPHE website:
https://www.colorado.gov/pacific/cdphe/norovirus-and-viral-gastroenteritis
CDC website:
http://www.cdc.gov/norovirus/index.Html
CDC Vital Signs dedicated to norovirus:
http://www.cdc.gov/vitalsigns/Slide189
EvaluationWrite notes on index cards.Slide190
Overall, how would you rate this training?
Excellent
Very Good
Good
Fair
PoorSlide191
After this training, I feel better prepared to investigate a foodborne outbreak
Strongly Agree
Agree
Disagree
Strongly DisagreeSlide192
Going through an outbreak scenario was beneficial.
Strongly Agree
Agree
Disagree
Strongly DisagreeSlide193
I practiced outbreak investigation skills during the training.
Strongly Agree
Agree
Disagree
Strongly DisagreeSlide194
Training materials (slides, handouts, flashdrive) were helpful.
Strongly Agree
Agree
Disagree
Strongly DisagreeSlide195
How were the organizational and presentation skills of the instructors?
Excellent
Very Good
Good
Fair
PoorSlide196
Thank you!