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Communicable Disease Epidemiology

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Plague. Polio. Rabies. Rubella. Pertussis. Q fever. Salmonellosis (incl. ... diagnosed as pneumonic plague; confirmation pending ... Pneumonic plague ... – PowerPoint PPT presentation

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Title: Communicable Disease Epidemiology


1
Communicable Disease Epidemiology Public Health
Surveillance An Overview
  • Amy D. Sullivan, PhD, MPH
  • Epidemiologist
  • Multnomah County Health Dept.

2
  • Unlike a forest fire, in a bioterrorism (BT)
    event

Population at risk!
  • Seeing the fire requires capturing
    epidemiologic data
  • Responding requires using that data

3
Topics in Presentation
  • Basic principles
  • Communicable disease epidemiology
  • Public health surveillance
  • Disease and outbreak reporting (local, state, and
    federal roles)
  • Adapting for Incident Command System

4
Basic Principles
5
Epidemiologic Science
  • Disagreement and confusion about basic ideas in
    epidemiology do not necessarily attest to the
    thick-headedness of epidemiologists a more
    charitable interpretation is that the basic
    ideas fundamental to this new science have not
    yet displaced traditional thinking.
  • Rothman and Greenland, Modern Epidemiology

6
What Is Epidemiology?
  • Studying the distribution determinants of
    health-related states in specific populations to
    control health problems
  • Usually human, but veterinary too
  • Diseases or conditions
  • Demand a set of actions as outcome

7
Sub-Specialties
  • Chronic
  • Environmental
  • Social
  • Reproductive
  • Infectious disease
  • Acute Communicable
  • Chronic Communicable

8
Doing Epi
  • Assess patterns of disease in populations
  • Identify potential risks for disease
  • Decrease/eliminate risk of disease
  • Describe disease in population by Person, Place,
    and Time

9
Person
  • How many
  • Clinical characteristics
  • Medical history
  • Immunization status
  • Demographic characteristics
  • Age, sex
  • Race/ethnicity/culture

10
Place and Time
  • Place
  • Geographic clustering
  • Association with a point source
  • Time
  • Clustering in time
  • Rate of development of new cases

11
Epidemiologic Triad
Host
Agent
Environment
12
Epidemiologic Triad
Host
Agent
Person Place Time
Environment
13
Epidemiologic Triad
Agent
Host
Environment
14
Epidemiology in Public Health Practice
  • Public Health Surveillance
  • Outbreak illness cluster investigation
  • Special studies
  • Resolve issues of detection bias or small numbers
  • Program design evaluation

15
Public Health Surveillance
  • ongoing systematic collection, analysis,
    interpretation, and dissemination of data on
    health-related events to reduce morbidity and
    mortality and to improve health

16
Passive vs. Active
  • Passive Surveillance
  • Wait for reports to arrive
  • Active Surveillance
  • Go out and collect information
  • Example Medical record reviews

17
Purposes of Surveillance
  • Allow assessment of health status of a given
    population
  • Provide quantitative basis to
  • Set priorities
  • Define strategies objectives for action
  • Evaluate interventions/programs/ outcomes

18
How Surveillance is Used
  • Routine Surveillance
  • Detect cases of disease of public health
    significance
  • Detect outbreaks and illness clusters
  • Event-specific surveillance
  • Monitor progression of event
  • Assess utility of intervention

19
Outbreaks and Clusters
  • Unusual amount of illness in a given population
    at a given time
  • Influenza
  • In 1 week, deaths due to pneumonia influenza
    (122 U.S. cities) exceeds 8.1
  • Foodborne Illness
  • Persons from 2 households share a specific meal
    have similar symptoms
  • Smallpox
  • 1 case anywhere in the world

20
Conditions Under Which Epi Field Investigation
Occurs
  • Situations where
  • Event unexpected
  • Immediate response required
  • Extent of investigation limited by need for
    timely intervention
  • Assess urgency of event

21
Factors Affecting Urgency
  • Severity of illness
  • Unusualness of occurrence
  • Extent of outbreak
  • Numbers of persons/households/sites
  • Timely intervention possible
  • Institutional support
  • E.g., hospital with infectious disease
    professionals involved

22
Preliminary Response
  • Symptom profile of initially reported person(s)
  • Confirm diagnosis
  • Onset dates duration of illness
  • Characteristics of affected persons
  • Demographics, recent travel
  • Pertinent medical history
  • If others similarly affected
  • Confirm diagnoses!

23
Elements of an Epidemiologic Field Investigation
  • Determine existence of epidemic (including
    confirming diagnoses)
  • Orient info by person/place/time
  • Develop case definition count cases
  • Develop and test hypotheses on specific exposures
    causing illness
  • Identify persons at risk
  • Execute control and prevention measures
  • Write-up plan for further study

24
Essential Tasks of Investigation
  • Investigation
  • Data collection analysis
  • Case interviews contact tracing
  • Surveillance
  • Monitoring
  • Active surveillance with affected institution(s)
  • Evaluation of interventions
  • Communications, managing personnel, etc.

25
Conducting Epi Field Investigations at MCHD
  • Routine activity for some programs
  • Communicable Disease
  • Environmental Health
  • STD
  • TB
  • Large event requires surge capacity

26
Disease and Outbreak Reporting in Oregon
27
Disease Outbreak Reporting in Oregon
  • Specific conditions defined by Oregon
    Administrative Rules,
  • Chapter 333
  • Divisions 12, 17, 18, 19, 24, 56
  • Legally required reporting through physicians and
    labs
  • Passive surveillance

28
Reported by Physicians(Excluding STDs)
  • OTHER
  • Animal bites
  • Any Arthropod-borne infection7
  • HUS
  • Lead poisoning
  • Marine intoxications
  • Any Outbreak of disease
  • Pesticide poisoning
  • Any Uncommon illness of
  • potential public health
  • significance
  • TIMING OF REPORTS
  • Immediatelyday or night
  • Within 24 hours
  • Within 1 working day
  • Within 1 week

Malaria Measles (rubeola) Meningococcal disease
Plague Polio Rabies Rubella Pertussis Q
fever Salmonellosis (incl. typhoid) Shigellosis Ta
enia solium/Cysticercosis Tetanus Trichinosis Tube
rculosis Tularemia Vibrio infection Yersiniosis
  • Anthrax
  • Botulism
  • Brucellosis
  • Campylobacteriosis
  • Cryptosporidiosis
  • Cyclospora infection
  • Diphtheria
  • Escherichia coli (Shiga-tox.)
  • Giardiasis
  • Haemophilus influenzae
  • Hantavirus
  • Hepatitis A
  • Hepatitis B
  • Hepatitis C (new infections)
  • Hepatitis D (delta)
  • Legionellosis
  • Leptospirosis
  • Listeriosis
  • Lyme disease

29
Lab Reportable Only
  • Tick-borne illnesses
  • Ehrlichia
  • Rickettsia
  • Lab reporting often more reliable than physician
    reporting

30
Response to Reports
  • Report or diagnosis confirmed by local Community
    Health Nurse
  • State receives notification assists as requested
  • Follow-up locally
  • Investigative Guidelines

31
Investigative Guidelines
  • For most reportable conditions
  • Disease Reporting
  • The Disease and Its Epidemiology
  • Case Definitions, Diagnosis, and Laboratory
    Services
  • Routine Case Investigation
  • Controlling Further Spread
  • Managing Special Situations

32
Overview of Local, State, and Federal Roles
  • LHD has public health authority in Oregon
  • State
  • Track data on public health conditions
    reporting federal level
  • Support LHD
  • Liaison with other states and federal
  • Federal
  • National disease reporting data
  • Support state and local health departments
  • Control/release certain pharmaceuticals

33
State Structure
34
Role of the State in an Investigation
  • Receive information on reportable condition
  • Timeframe set out in BT/CD Assurances
  • Notification summary of findings/actions
  • Support multi-county investigations
  • Counties decide on lead state assists
  • Support/conduct investigation if county resources
    inadequate
  • Get LHD agreement
  • Liaise with CDC
  • Technical advise, obtain pharmaceuticals/
    vaccines, etc

35
Other Aspects of Local-State Relationship
  • State not a regulatory agency
  • State does control funds
  • In a declared emergency, State Health Officer has
    expanded powers

36
Federal Structure
37
Role of the CDC in an Investigation
  • Support state and local public health
  • Technical experts
  • Laboratory testing
  • Pharmaceuticals vaccines
  • Lead multi-state outbreaks
  • Coordinate information nationally
  • Liaise with other countries international
    organizations

38
Epi Activities in an ICS Context
39
Possible BT Event ICS Structure (Epi Functions)
40
Operations Section Epi Field Activities
  • Hospital-Based Surveillance
  • Active surveillance case finding
  • Info on medical management
  • Case Investigation
  • Confirm cases assure appropriate specimens
    collected
  • Detailed interviews
  • Medical social history and possible contacts
  • Contact Tracing
  • Follow-up with contacts case finding
  • Education, symptoms, prophylaxis, additional
    contacts

41
Planning Section Epi Planning
  • Epidemiologic information needed to direct
    operations
  • Plan investigation
  • Develop provide materials training
  • Assure collection entry of data from Ops epi
    field activities
  • Analyze and summarize epi data
  • Case numbers disease rates
  • Populations at risk prophylaxed

42
Scenario Example
43
Scenario First Report
  • MCHD Communicable Disease Program receives these
    two reports
  • A County jail prisoner has died 1 staff 4
    other inmates in hospital w/ similar symptoms
  • Symptoms chills, high fever, body pains, chest
    discomfort, and a very bad cough
  • Local hospital ICP reports 2 ED workers
    hospitalized with a serious respiratory illness

44
Factors Affecting UrgencyScenario Example
  • Severity 1 death 5-7 hospitalized
  • Unusualness Age / time of year / possible
    number
  • Extent gt1 institution
  • Timely intervention possible ?
  • Institutional support Good, but might involve
    multiple institutions

45
Preliminary Response Scenario Example
  • Symptom profiles
  • Comparable symptoms among all ill onsets within
    2 days
  • Initial inmate died within 3 days
  • Characteristics of affected persons
  • Initial inmate homeless man arrived in town
    within 2 days of arrest
  • ED workers worked same shift recent death in ED
    on that shift

46
Scenario Day 2
  • Corrections
  • Dead inmate diagnosed as pneumonic plague
    confirmation pending
  • Additional ill
  • 2 corrections officers 1 nurse 8 inmates
  • Hospital
  • Pneumonic plague diagnosed in both HCWs
  • 1 HCW died Other seriously ill child of dead
    HCW symptomatic
  • 20 total cases (17 from Corrections, 3 from
    hospital) with 2 deaths
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