Title: Communicable Disease Epidemiology
1Communicable 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
3Topics in Presentation
- Basic principles
- Communicable disease epidemiology
- Public health surveillance
- Disease and outbreak reporting (local, state, and
federal roles) - Adapting for Incident Command System
4Basic Principles
5Epidemiologic 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
6What 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
7Sub-Specialties
- Chronic
- Environmental
- Social
- Reproductive
- Infectious disease
- Acute Communicable
- Chronic Communicable
8Doing 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
9Person
- How many
- Clinical characteristics
- Medical history
- Immunization status
- Demographic characteristics
- Age, sex
- Race/ethnicity/culture
10Place and Time
- Place
- Geographic clustering
- Association with a point source
- Time
- Clustering in time
- Rate of development of new cases
11Epidemiologic Triad
Host
Agent
Environment
12Epidemiologic Triad
Host
Agent
Person Place Time
Environment
13Epidemiologic Triad
Agent
Host
Environment
14Epidemiology in Public Health Practice
- Public Health Surveillance
- Outbreak illness cluster investigation
- Special studies
- Resolve issues of detection bias or small numbers
- Program design evaluation
15Public Health Surveillance
- ongoing systematic collection, analysis,
interpretation, and dissemination of data on
health-related events to reduce morbidity and
mortality and to improve health
16Passive vs. Active
- Passive Surveillance
- Wait for reports to arrive
- Active Surveillance
- Go out and collect information
- Example Medical record reviews
17Purposes 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
18How 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
19Outbreaks 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
20Conditions 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
21Factors 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
22Preliminary 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!
23Elements 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
24Essential 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.
25Conducting Epi Field Investigations at MCHD
- Routine activity for some programs
- Communicable Disease
- Environmental Health
- STD
- TB
- Large event requires surge capacity
26Disease and Outbreak Reporting in Oregon
27Disease 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
28Reported 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
29Lab Reportable Only
- Tick-borne illnesses
- Ehrlichia
- Rickettsia
- Lab reporting often more reliable than physician
reporting
30Response to Reports
- Report or diagnosis confirmed by local Community
Health Nurse - State receives notification assists as requested
- Follow-up locally
- Investigative Guidelines
31Investigative 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
32Overview 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
33State Structure
34Role 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
35Other Aspects of Local-State Relationship
- State not a regulatory agency
- State does control funds
- In a declared emergency, State Health Officer has
expanded powers
36Federal Structure
37Role 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
38Epi Activities in an ICS Context
39Possible BT Event ICS Structure (Epi Functions)
40Operations 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
41Planning 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
42Scenario Example
43Scenario 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
44Factors 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
45Preliminary 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
46Scenario 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