Epidemiology and Public Health Preparedness

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Epidemiology and Public Health Preparedness
Kristen Pogreba-Brown, MPH
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Learning Objectives

• Describe public health preparedness
• Describe the role of Epidemiologists in
  preparedness
  
• List events that may require a public health
  response
  
• Explore ways in which Promotores can participate
  in a public health emergency response
  

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Learning Objectives cont.

• Describe the general layout of an Incident
  Command Structure
  
• Describe why public health investigates
  outbreaks
  
• List the basic steps involved in conducting an
  outbreak investigation
  
• Conduct an investigative interview

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The Need for Public Health Preparedness

• The possibility of public health emergencies
  arising in the United States concerns many people
  in the wake of recent hurricanes, tsunamis, acts
  of terrorism, and the threat of pandemic
  influenza. Though some people feel it is
  impossible to be prepared for unexpected events,
  the truth is that taking preparedness actions
  helps people deal with disasters of all sorts
  much more effectively when they do occur.
  Centers for Disease Control and Prevention

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Stages Surrounding an Event
EVENT
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What is Public Health Preparedness?

• Planning, Planning, Planning!!
• Training and Education
• Engaging community partners in discussion of
  their needs
  
• Addressing the challenges of special needs
  populations
  
• Creating partnerships across various agencies and
  jurisdictions

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What Types of Events would PH Respond to?

• Infectious Disease Outbreaks
• Wild Land Fires
• Terrorism or Bioterrorism Events
• Environmental Disasters
• Large-scale Industrial Accidents
• Natural Disasters
• Mass Casualties

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Pictures
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PH Following a Natural Disaster

• Goal is to safeguard the population from disease
  related to
  
• Sanitation
• Personal hygiene
• Water supply
• Diarrheal disease
• Heating and shelter
• Mental Health

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Public Healths Role During an Event

• Activate emergency response plan
• Road map of when and how to respond
• Deploy personnel
• Trained persons to a command center
• Evaluate information
• Agencies can conduct epidemiology investigations
  or enhanced surveillance
  
• Invoke public health emergency powers
• Mandatory testing reporting procedures

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Public Healths Role During an Event cont.

• Coordinate medical services
• Overflow to other treatment facilities
• Monitor requests for support
• More equipment, supplies, or personnel
• Deactivate emergency response plan
• Depends on the level of threat remaining

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What Other Agencies Does Public Health Partner
With?

• Emergency Management, FEMA
• Law Enforcement, Fire Department, National Guard
• EMS, Red Cross, health care providers, hospitals
• Medical examiners
• Mental health agencies and providers
• Clinical labs, Public health labs
• Environmental and Agricultural agencies
• Department of Public Works
• Tribal Counter-Parts
• Non-Governmental Organizations

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National Incident Management System

• NIMS
• A system for achieving unified interagency
  management during emergency response operations
  
• Training in NIMS courses required for individuals
  to be compliant
  
• Funding for agencies reliant upon their employees
  being trained

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National Incident Management System

• What does all that mean?
• Everyone needs to speak the same language
• Systems need to work together
• Agreements need to be put in place ahead of time
  to share resources
  

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Incident Command Structure

• ICS is a management organization tool that unites
  all emergency response agencies into one cohesive
  and coherent system, enabling responders at all
  levels (local, state, and national) to work
  together more effectively and efficiently to
  manage domestic incidents no matter what the
  cause, size or complexity.

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ICS Features

• Flexible
• Can expand and contract
• Common nomenclature/language
• Management by objectives
• Clearly defined chain of command
• Clearly delineated functional roles
• Positions within ICS are not necessarily related
  to a persons everyday job function
  

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ICS General Chain of Command
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ICS Knowing your Role

• May not be the same as your everyday roles, but
  some of the same skills may overlap
  
• It may vary depending on the incident

• Ways to Prepare
• Become familiar with any emergency response plans
  your agency might have and consider ways you may
  be involved
  

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Questions?
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What are Potential Roles for Promotoras in a
Public Health Event?
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What is an Outbreak?

• A sudden rise in the incidence of a disease
• Clinician, infection control nurse, or clinical
  laboratory worker first notices an unusual
  disease or an unusual number of cases of a
  disease and alerts public health officials

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Outbreak Investigations

• Public health is rooted in the investigation of
  infectious disease outbreaks.
  
• Infectious disease outbreak investigations are
  initiated and conducted at the local level.
  

• Local health departments are responsible for all
  of the steps of an outbreak investigation and
  work with larger state or federal agencies during
  large-scale events.

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Why Does PH Investigate Outbreaks?

• Control and Prevention
• Help identify the source of ongoing outbreaks and
  prevent additional cases
  
• Research Opportunities
• Thorough investigations often can increase
  knowledge of a given disease and prevent future
  outbreaks
  
• Training
• Public, Political, or Legal Concerns
• Program Considerations

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Basic Steps for Outbreak Investigations

• Prepare for Fieldwork
• Confirm the Existence of an Outbreak
• Verify the Diagnosis
• Define Case Definition
• Identify Cases and Exposed Persons
• Develop a Questionnaire
• Choose a Study Design
• Descriptive Epidemiology
• Formulate, Evaluate and Refine the Hypothesis
• Conduct Studies
• Implement Control and Prevention Measures
• Communicate Findings

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Basic Steps for Outbreak Investigations

• Verify the diagnosis and confirm the outbreak
• Confirm laboratory testing
• Rule out misdiagnoses or laboratory error
• Define a case and conduct case findings
• Develop a specific case definition using
• Symptoms or laboratory results
• Time period
• Location
• Conduct surveillance using case definition
• Existing surveillance
• Active surveillance (e.g. review medical
  records)
  
• Interview case patients

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Basic Steps for Outbreak Investigations cont.

• Count/record and orient data time, place,
  person
  
• Create line listing (case plotted on a graph)
• Person
• Who was Infected?
• What do the cases have in common?
• Place
• Where were they infected?
• May be useful to draw a map
• Time
• When were they infected?
• Create an epidemic curve

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Basic Steps for Outbreak Investigations cont.

• Take immediate control measures
• If an obvious source of contamination is
  identifiedinstitute control measures
  immediately!
  
• Formulate and test hypothesis
• Develop hypothesis
• Literature reviews of previous outbreaks
• Interviews of several case-patients
• Conduct an analytic study to test hypotheses
• Retrospective cohort study
• Case-control study

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Basic Steps for Outbreak Investigations cont.

• Plan and execute additional studies
• Environmental sampling
• Collect appropriate samples
• Allow epidemiological data to guide testing
• If analytic study results are conclusive, dont
  wait for positive samples before implementing
  prevention
  
• Implement and evaluate control measures
• Prevent further exposure and future outbreaks by
  eliminating or treating the source
  
• Work with regulators, industry, and health
  educators to institute measures
  
• Create mechanism to evaluate both short- and
  long-term success

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Basic Steps for Outbreak Investigations cont.

• Communicate finding
• Identify a single member of the investigation
  team to interact with media and communicate
  progress and findings
  
• Summarize investigation, make recommendations,
  and disseminate report to all participants
  

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Partnering with an Epidemiologist

• Case Investigations
• Case Interviews
• Contact Tracing
• Case Follow-Up

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What is Epidemiology???

• Epidemiology is the study of disease trends
  within a specific population. It is used to
  describe, quantify and postulate the causal
  mechanisms for health related issues.

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Epidemiology Triad
Host
Pathogen
Environment
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Epidemic??

• Epidemics are defined as a number of cases of
  disease above the normal endemic number.
  
• How many cases are needed to qualify the event as
  an epidemic?

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How can I get sick?
Transmission of Disease

• Direct Transmission
• Droplet
• Body Fluid
• Close contact

• Indirect Transmission
• Vectors
• Food borne
• Fomites
• Airborne

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An Epis Definition of you

• Case someone who becomes ill with the disease
  in question
  
• Carrier/Reservoir someone who carries the
  disease and can pass it on to others but does not
  become ill themselves
  
• Susceptible you can get the disease
• Immune you cant get the disease (usually
  because you have already had it or had a
  vaccination against it)
  
• Control someone who did not get sick but has
  other similarities to the case (they needed to
  have the same likelihood of becoming exposed as
  the case)

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Is it an outbreak?

• In epidemiology, we LOVE statistics!!!
• The more numbers the betterso, weve designed a
  formula that will tell us if the results are
  real, or just due to chance.
  
• Odds Ratio measure of the odds of exposure of a
  given disease
  
• An OR of 1.0 means that the odds of exposure
  among cases and controls is the same (and implies
  that the exposure in question is not a risk
  factor for the disease in question)
• An OR above 1.0 implies a negative effect
• An OR less than 1.0 implies a protective effect
• Assuming your stats are set up correctly!

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Odds Ratios and 2 x 2 Tables

• Disease Status
• Yes No
• Exposure Yes
• Status
• No

a
b
c
d
OR ad/bc
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Outbreak! What do you do??

• The health department receives a phone call on
  Wednesday morning from a camp counselor. A group
  dinner was served Friday night and by Saturday
  night 7 people had become ill with
  gastrointestinal symptoms. Another 4 became ill
  on Sunday morning. Of the 11 students who became
  ill, 3 went to the doctor where a stool sample
  was collected and sent to the state lab. The
  results are pending. What do you do?

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Interviews and Data Collection

• Today, you will (for a short period) play the
  role of two people.
  
• The first role is that of a student who attended
  last weekss infamous dinner.
  
• The second role is of a public health worker who
  needs to interview the student to try and
  determine the source of infection.
  

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Tips for Interviewing

• Follow the questions in order
• Dont skip something because you dont think it
  applies or you think you already know the answer
  
• Be courteous
• People are telling you about an illness they have
  and in doing so are helping YOU out (they are not
  required to answer any of your questions)
  
• Dont be embarrassed
• Everyone has been sick at some point in their
  lives, but not everyone likes to talk about it in
  detail. If you are too uncomfortable to ask the
  question, they wont be comfortable in giving you
  the answers!

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Interviews

• Pair up and interview each other.
• Use the scripts to ask your questions.
• Use the information given to you to answer the
  questions.
  

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Updated Information

• The state lab called and confirmed that the three
  samples they received were positive for
  Salmonella.
  
• Symptoms of salmonellosis include
• Sudden onset of headache
• Abdominal pain
• Diarrhea
• Nausea
• Vomiting
• Mode of transmission
• Ingestion of the organisms in food derived from
  infected food-animals or contaminated by the
  feces of an infected animal or person
  
• Includes raw or undercooked eggs, milk or milk
  products, meat, poultry
  
• Also associated with pet turtles and reptiles
• Incubation period
• From 6 to 72 hours (usually 12-36 hours)

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Line Lists

• Make a list of everyone who attended the event,
  what they ate, and whether or not they became
  ill.
  
• Do you notice any trends or items that should be
  investigated further?

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Line List Example
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Epi Curve

• Graphing the number of cases over time can show
  many things
  
• When the outbreak began
• A possible index case for the outbreak
• Length of time that people became ill
• Is the outbreak still occurring?

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Epi Curve for this Outbreak
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What made me sick?

• In many foodborne outbreaks, investigators will
  never find out the exact food that made people
  illwhy?
  
• Bad recall
• Cross contamination
• Too many foods to analyze

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2 x 2 Tables for this Outbreak
Disease-Yes
Disease-No
Exposure-Yes
Pizza
Exposure-No
Ice Cream
Chicken
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Odds Ratios for this Outbreak

• Pizza 2.0
• Chicken .0667
• Ice Cream 11.0
• People who were ill were two times more likely to
  have eaten pizza and 11 times more likely to have
  eaten ice cream over people who did not become
  ill!

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Public Health Implications

• What, as public health professionals, do you do
  with this information?
  
• What, if anything, can you do to prevent people
  from becoming ill in the future?

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Recent Salmonella Outbreaks

• As of March 7th 2007, 425 persons infected with
  the outbreak strain of Salmonella Tennessee have
  been reported to CDC from 44 states.
  
• Among 351 patients for whom clinical information
  is available, 71 (20) were hospitalized.
  
• No deaths have been attributed to this
  infection.
  
• Product testing has confirmed the presence of the
  outbreak strain of Salmonella Tennessee in opened
  jars of peanut butter obtained from ill persons.
  
• How did the CDC determine this outbreak was
  occurring?
  
• Investigation same manufacturing plant in
  Georgia
  
• Surveillance - PulseNet

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QUESTIONS???