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Public Health Information Network (PHIN)
Series I
is for Epi
Epidemiology basics for non-epidemiologists
Series Overview
Introduction to:
• The history of Epidemiology
• Specialties in the field
• Key terminology, measures, and resources
• Application of Epidemiological methods
Series I Sessions
Title Date
“Epidemiology in the Context of Public Health”
January 12
“An Epidemiologist’s Tool Kit” February 3
“Descriptive and Analytic Epidemiology”
March 3
“Surveillance” April 7
“Epidemiology Specialties Applied” May 5
Session I – V Slides
VDH will post PHIN series slides on the following Web site:
http://www.vdh.virginia.gov/EPR/Training.asp
NCCPHP Training Web site:
http://www.sph.unc.edu/nccphp/training
Site Sign-in Sheet
Please submit your site sign-in sheet andsession evaluation forms to:
Suzi SilversteinDirector, Education and Training
Emergency Preparedness & Response Programs
FAX: (804) 225 - 3888
Series ISession IV
“Surveillance”
What to Expect. . .
TodayIntroduction to the applications, limitations, and interpretation of public health surveillance data
Session Overview
• Introduction to Public Health Surveillance– Passive, active, and syndromic surveillance– VA communicable disease law– Paper-based surveillance of reportable diseases– Applications and limitations
• Federal Public Health Surveillance– CDC’s role– Data sources– Surveillance reporting examples
Session Overview (cont’d.)
• Techniques for Review of Surveillance Data– Considerations when working with surveillance data– Access data sources for rate numerators and
denominators– Descriptive epidemiology– Graph and map surveillance rates
Today’s Learning Objectives
Upon completion of this session, you will:
• Recognize the applications and limitations of current public health surveillance practices
• Understand the function of three different types of surveillance: active, passive, and syndromic
• Be familiar with federal public health surveillance systems relevant to epidemiology programs
Today’s Learning Objectives
• Understand the reciprocal pathway of data exchange through county, state, and federal surveillance efforts
• Be familiar with the Virginia paper-based surveillance system for reportable diseases
• Recognize the potential benefits of National Electronic Disease Surveillance System (NEDSS) implementation in Virginia
• Recognize the utility of Epi Info software for surveillance data analysis
Today’s Presenters
Amy Nelson, PhD, MPHConsultantNCCPHP
Lesliann Helmus, MSSurveillance ChiefDivision of Surveillance and InvestigationOffice of Epidemiology, Virginia Department of Health
Sarah Pfau, MPHConsultantNCCPHP
What is Surveillance?
What is Surveillance?
CDC: The ongoing systematic collection, analysis, and interpretation of health data, essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination to those who need to know.
-Physicians
-Laboratories
-STD clinics
-Community health clinics
County and state health departments and CDC who analyze data using statistical methods
Standardized data collection
-Physicians
-Laboratories
-STD clinics
-Community health clinics
County and state health departments and CDC who analyze data using statistical methods
-Public health officials
-Health directors
-Health policy officials
Standardized data collection
Dissemination to those who need to know
Dissemination to those who need to know
-Physicians
-Laboratories
-STD clinics
-Community health clinics
County and state health departments and CDC who analyze data using statistical methods
-Public health officials
-Health directors
-Health policy officials
Change in public health practice (vaccination, reduction of risk factors, medical intervention, etc.)
Standardized data collection
Dissemination to those who need to know
Dissemination to those who need to know
Public health planning and intervention
-Physicians
-Laboratories
-STD clinics
-Community health clinics
County and state health departments and CDC who analyze data using statistical methods
-Public health officials
-Health directors
-Health policy officials
Change in public health practice (vaccination, reduction of risk factors, medical intervention, etc.)
Standardized data collection
Dissemination to those who need to know
Dissemination to those who need to know
Public health planning and intervention
Public health evaluation
NNDSS & NETSS
• The National Notifiable Disease Surveillance System (NNDSS)
• Disease-specific epidemiologic information
• 60 nationally notifiable infectious diseases
• 10 non-notifiable infectious diseases
• The National Electronic Telecommunications System for Surveillance (NETSS)
Elements of Surveillance
• Mortality reporting – legally required• Morbidity reporting – legally required• Epidemic reporting• Timely reporting• Laboratory investigations• Individual case investigations• Epidemic field investigations• Analysis of data
Types of Surveillance
• Passive
• Active
• Syndromic
Passive Surveillance
Laboratories, physicians, or other health care providers regularly report cases of disease to the local or state health department based on a standard case definition of that particular disease.
Communicable Disease Reporting:Passive Surveillance
Hospital PhysicianLab
LHD
State
CDC
Public
VA Reportable Diseases
http://www.vdh.state.va.us/epi/list.asp
VA Epi-1 Reporting Form for Paper-based Surveillance
VA Communicable Disease Law
Communicable disease statutes are in Chapter 2 of Title 32.1 of the Code of Virginia.
http://www.vdh.state.va.us/epi/appendxb.pdf
These articles are incorporated into and referenced throughout the State Board of Health’s Regulations for Disease Reporting and Control
http://www.vdh.state.va.us/epi/regs.pdf
Active Surveillance
Local or state health departments initiate the collection of specific cases of disease from laboratories, physicians, or other health care providers.
Communicable Disease Reporting:Active Surveillance
Hospital PhysicianLab
LHD
State
CDC
• Outbreak investigations
• Other times when complete case ascertainment is desired (e.g., research study)
Active Surveillance Applications
Question & Answer Opportunity
Syndromic Surveillance
The ongoing, systematic collection, analysis, interpretation, and application of real-time indicators for disease that allow for detection before public health authorities would otherwise identify them.
What are “indicators of disease?”
“Indicators” are clinical signs that we can categorize into syndromes, but NOT a
specific diagnosis!
Example:
Cough + Sore throat + Fatigue + Fever = Influenza-Like Illness
Common Syndromesunder Surveillance
• Gastroenteritis
• Influenza like illness (ILI)
• Meningitis / Encephalitis
• Rash / Fever
• Botulinic• Hemorrhagic
Why Do Syndromic Surveillance?
• Early detection of clusters in naturally occurring outbreaks or a BT event– Minimizes mortality & morbidity
• Characterize outbreak– Magnitude, rate of spread, effectiveness of control
measures
• Quick investigation
• Detection of unexplained deaths
Syndromic vs. Traditional Surveillance
00.10.20.30.40.50.60.70.80.9
1
0 24 48 72 96 120 144 168
Incubation Period (Hours)
Dis
ease
Det
ectio
n
Gain of 2 days
Effective Treatment Period
Traditional DiseaseDetection
Phase IIAcute Illness
Phase IInitial Symptoms
Early Detection
Source: Johns Hopkins University / DoD Global Emerging Infections System
Limitations of Syndromic Surveillance
• Inadequate specificity: false alarms– Uses resources in investigation
• Inadequate sensitivity: failure to detect outbreaks/BT events– Outbreak is too small– Population disperses after exposure,
cluster not evident
Limitations of Syndromic Surveillance
• Costly
• Staff expertise required
• Formal evaluation of syndromic surveillance systems are incomplete
Surveillance Applications
Applications• Establish Public Health Priorities
• Aid in determining resource allocation
• Assess public health programs– Facilitate research
• Determine baseline for detection of epidemics
• Early detection of epidemics– Estimate magnitude of the problem– Determine geographical distribution
Establish Public Health Priorities:
• Frequency (incidence / prevalence, mortality, years of life lost)
• Severity (case fatality rate, hospitalization, disability)
• Cost (direct, indirect)
Resource AllocationTUBERCULOSIS: Reported cases per 100,000 population,
United States and U.S. territories, 2002
Source: http://www.cdc.gov/dphsi/annsum/index.htm
Assess Public HealthPrograms
Data Graphed by Race and Ethnicity
Gonorrhea: reported cases per 100,000 population,United States, 1987 - 2002
Source: http://www.cdc.gov/dphsi/annsum/index.htm Data Graphed by Gender
*For 120 cases, origin of patients was unknown.
TUBERCULOSISamong U.S.-born and foreign-born persons, by year, United States, 1990-2002
Determine Baseline Rates
Early Detection of Epidemics0
5010
015
020
0N
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Number of flu patients by monthBoston, MA
Surveillance Limitations
Limitations
• Uneven application of information technology – Paper-based versus Electronic
• Timeliness– Reporting time requirement– Reporting burden
• Completeness– Unreported cases– Incomplete reports
CDC
Varied communications methods and security - specific to each system- including paper forms, diskettes, e-mail, direct modem lines, etc.
Current Situation
MMWR Weekly TablesMMWR Annual
SummariesProgram Specific Reports and
Summaries
State Health Dept
TIMSSTD*MIS
HARS
HARS STD*MIS TIMS NETSS EIP Systems
NETSS
STD*MIS (Optional at the Clinic)
TIMS (Optional
at the Clinic)
PHLISEIP System
s*
PHLIS
HARS STD*MIS
TIMS NNDSS EIP Systems
PHLIS
* EIP Systems (ABC, UD, Foodnet)
Data Source
sPhysici
ans
Varied communications methods and security - specific to each system - including diskettes, e-mail, direct modem lines, etc.
Chart Review
Lab Repor
ts
Reporting by Paper
Form, Telephone
& Fax
Statistical Surveys for
Chronic Diseases,
Injuries and Other Public
Health Problems
City/County Health Department
Limitations: Multiple Categorical Systems
National Electronic Disease Surveillance System (NEDSS)
• NEDSS is not a surveillance system
• Electronically integrate existing surveillance systems for easy data collection, storage and access
• Security to meet confidentiality needs
Guest Lecturer:Virginia’s Surveillance
Practices and Challenges
Lesliann Helmus, MS
Surveillance Chief
Division of Surveillance and Investigation
Office of Epidemiology, VDH
Overview
• Challenges in conducting surveillance
• NEDSS – tool to improve surveillance
• Application – Hepatitis A example
Surveillance Challengesin Virginia
• Quality of the data
• Balancing priorities
• Discrepancies and perspectives
• Translating data into information
Quality of the data
“The Government is very keen on amassing statistics. They collect them, add them, raise them to the nth power; take the cube root and prepare wonderful diagrams. But you must never forget that everyone of these figures comes in the first instance from the village watchman who puts down what he damn well pleases.”
Sir Josiah Stamp (1896-1919) - Head of the Inland Revenue Department of the UK
Quality of the Data
• Completeness of case ascertainment
• Completeness and accuracy of case information
• Timeliness of reports
• Sentinel indicators
‘Tip of the iceberg’
Reporter
RegionalOffice
CentralOffice
District
Flow of Reports in Virginia
CDC
Central Office
District
Quality of the Data
• Completeness of case ascertainment
• Completeness and accuracy of case information
• Timeliness of reports
• Sentinel indicators
‘Tip of the iceberg’
Balancing Priorities
Year Reported
HCV+ Test Results*
Acute Hep C Cases
Acute Hep A Cases
2001 1,265 3 167
2002 1,365 15 163
2003 4,313 15 141
2004 10,725 21 145
*Numbers may be inflated due to duplicates
Discrepancies and Perspectives
• Clinical vs surveillance case definitions
• Cases ‘worked’ vs cases ‘counted’
• Place of exposure, residence, diagnosis
• Re-infection or duplicate report
• Stats by date of onset, diagnosis, report
Translating Data into Information
• Provides the basis for public health action
• Requires sound analysis and interpretation
• Extracts meaningful, actionable findings
• Requires clear presentation of complex issues
NEDSS
A Tool to Improve Surveillance
National Electronic Disease Surveillance System
• Centralized data system for disease surveillance in Virginia
• Person based system – links health events• Accessed through the VDH network• Ensures data confidentiality and integrity• Supports electronic data submissions• Will modify processes for managing reports
Benefits from NEDSS
• Faster recognition of health problems– Electronic transmission from large facilities
(provides better data, faster)– Simultaneous district/region/central office
access to the data
Benefits from NEDSS
• Greater consistency in data interpretation– Shared case status (cases definitions)– Shared dates– ‘As needed’ guidance and coaching– Shared updates– Shared reports
Benefits from NEDSS
• Shift in effort– Cases entered once– Trail for chronic cases– Processing of electronic transmissions– Ability to monitor reporters activity
Benefits from NEDSS
• Bigger picture– Earlier look at data across jurisdictions– Identification of people with co-infections– More effective analysis across diseases
Benefits from NEDSS
• Shared tools– High level tools with low level maintenance for
users– Shared expertise
Surveillance Application Example
Hepatitis A
Example – Hepatitis A
Source: Virginia Disease Control Manual
Reporting
• Initial report – Phone call – 24/7 availability of Health Dept– Would trigger follow-up with case
• Follow-up documentation– Clinical (‘morbidity’) report– Laboratory report
Enter Information into NEDSS
Key Information from Provider
Laboratory Report Information
Patient Interview:Risk Information
Look for Bigger Picture
• Sporadic case ?• Part of ongoing
outbreak ?• Beginning of new
outbreak ?
• Day care age?• Subgroup? • General community?
Surveillance Data Analysis:Line Lists
Surveillance Data Analysis:Cross-tabs
Age Group
Risk 0-4 5-19 20-64 65+
Foodservice 0 0 3 0
Daycare 1 0 0 0
No Risk 0 1 2 1
Hepatitis A Cases Reported in the Past Week
Surveillance Data Analysis:Time Trends
Confirm Case – Submit Notification
Statewide Review and Analysis
• Monthly data http://www.vdh.state.va.us/epi/Data/month04.asp
• Annual Data http://www.vdh.state.va.us/epi/Data/annual02.asp
• Virginia Epidemiology Bulletin http://www.vdh.state.va.us/epi/bulletin.asp
• See Your District Epidemiologist
Question & AnswerOpportunity
5 minute break
Federal Public Health Surveillance
CDC’s Role in Surveillance
• Support the states– Provide training and consultation in public
health surveillance– Distribute and oversee funding
• Receive, collate, analyze, and report data• Suggest changes to be considered in
public health surveillance activities• Report to the World Health Organization
as required and appropriate
TABLE II. Provisional cases of selected notifiable diseases, United States, weeks ending June 5, 2004, and May 31, 2003 (22nd week)
CDC Surveillance Data Reporting
Federal Data Sources
• Over 100 federal surveillance systems• Collect data on over 200 infectious and non-
infectious conditions such as:– Active Bacterial Core Surveillance (ABCs)– Foodborne Diseases Active Surveillance Network
(FoodNet)– National West Nile Virus Surveillance System
(ArboNet)– Viral Hepatitis Surveillance Program (VHSP)– Waterborne-Disease Outbreak Surveillance System– Influenza Sentinel Physicians Surveillance Network
Federal Surveillance Resources
• CDC Morbidity and Mortality Weekly Report (MMWR)
http://www.cdc.gov/mmwr
• CDC Office of Surveillance http://www.cdc.gov/ncidod/osr/index.htm
Council of State and Territorial Epidemiologists (CSTE)
http://www.cste.org
• Collaborates with CDC to recommend changes in surveillance, including what should be reported / published in MMWR
• Develops case definitions
• Develops reporting procedures
Example: ArboNet
• ArboNet is a cooperative surveillance system maintained by CDC and 57 state and local health departments for detecting and reporting the occurrence of domestic arboviruses.
ArboNet - Data
• Human – Encephalitis, meningitis, fever, viremic blood
donors, other
• Dead bird
• Equine
• Mosquito
• Sentinel animals (chicken, pigeon, horse)
• Other non-human mammals
ArboNet – Surveillance Issues
• “Real-time” reporting– Novel occurrence of West Nile virus– Web-based reporting (states)– Still relies on paper-based reporting (local)
• Incorporates ecologic data
• NEDSS compatible
• Duplicity of human case reporting
ArboNet - Diseases
• West Nile virus• St. Louis Encephalitis virus• Eastern Equine Encephalitis virus• Western Equine Encephalitis virus• California serogroup viruses (i.e., La Crosse)• Powassan Encephalitis virus• Japanese Encephalitis virus• Dengue virus
What is West Nile Virus?
• Transmitted to humans via bites from infected mosquitoes
• Infection usually asymptomatic; some people have fever, headache, rash, swollen lymph glands.
• No infections documented in the Western Hemisphere until 1999; then 46 U.S. states reported WNV activity in 2003!
Virginia Arboviruses
• VA Department of Healthhttp://www.vdh.virginia.gov/whc/external_whc/westnilevirus.asp
• VA Arbovirus Surveillance and Response Planhttp://www.vdh.virginia.gov/whc/external_whc/Avianplan2004.asp
• State Laboratory of Public Health (VA Department of General Services)
• VA Department of Agriculture and Consumer Services– Local Department of Agriculture Veterinary Laboratories
• VA Department of Game and Inland Fisheries
• U.S. Army Center for Health Promotion and Preventive Medicine
http://westnilemaps.usgs.gov/
Cumulative Dead Bird West Nile Virus Infections: 2004
http://westnilemaps.usgs.gov/
Cumulative Human West Nile Virus Cases: 2004
Cumulative Human West Nile Virus Cases: 2004
http://westnilemaps.usgs.gov
Video Clip:Public Health Grand Rounds
“Preparing for West Nile Virus: Will Your Community be Next?” (May 2001). GrandRounds@sph.unc.edu
Notice:• Surveillance lessons learned by public health officials • How the manifestation of the virus makes it easy to
involve the general public in surveillance efforts
• How quickly West Nile Virus has spread across the U.S. in only a few years
Example: Influenza
U.S. Influenza Surveillance
1. World Health Organization (WHO) and National Respiratory and Enteric Virus Surveillance System (NREVSS) collaborating laboratories
2. State and Territorial Epidemiologists’ Reports
3. 122 Cities Mortality Reporting System4. U.S. Influenza Sentinel Providers
Surveillance Network (voluntary)
U.S. Influenza Surveillance
Does. . .• Find out when and where
influenza is circulating • Determine what type of
influenza viruses are circulating
• Detect changes in the influenza viruses
• Track influenza-related illness
• Measure the impact influenza is having on deaths in the United States
Does Not. . .
Ascertain how many people have become ill with influenza during the influenza season
Influenza-like IllnessCase Definition
The Influenza-Like Illness case definition for CDC’s surveillance system is:
1. Fever of 100 degrees Fahrenheit or higher
2. AND cough OR sore throat.
CDC Sentinel Influenza Surveillance
http://www.cdc.gov/flu/weekly/
CDC Sentinel Influenza Surveillance
http://www.cdc.gov/flu/weekly/
VA Influenza Surveillance
Goal: “. . .to detect outbreaks of influenza as early and quickly as possible in order to facilitate early public health intervention and to specify the organisms involved.”
1. Passive surveillance2. Laboratory surveillance3. Active sentinel component
Virginia Active Sentinel Surveillance
• Virginia Department of Health conducts active surveillance with physicians around the state
– Season is October - April
– 60 – 70 physicians represent medical practices in each of the state’s five health planning regions
• Primarily family practice or internal medicine
VA Influenza-like Illness Surveillance Activity
http://www.vdh.state.va.us/epi/flu.htm
Access VA and CDC Reports
Reports of Influenza Activity in the
Virginia Surveillance Program:
http://www.vdh.state.va.us/epi/flu.htm
CDC reports and charts containing national and regional data:
www.cdc.gov/ncidod/diseases/flu/weekly.htm
Question & AnswerOpportunity
5 minute break
Guest Lecturer: Techniques for Analysis of
Surveillance Data
Sarah Pfau, MPH
Consultant, NCCPHP
Overview• Considerations when working with surveillance
data
• Descriptive Epidemiology
• Access surveillance data in Microsoft Excel or Access formats
• Access online census data
• Analyze surveillance data
Considerations
• Surveillance data primarily yield descriptive statistics
• Know the inherent strengths and weaknesses of a data set
• Examine data from the broadest to narrowest
Rely on Computers to:
• Generate Simple, Descriptive Statistics– Tables: frequencies, proportions, rates– Graphs: bar, line, pie– Maps: census tracts; counties; districts
• Aggregate or Stratify Rates– State versus county– Multiple weeks or months or years– Entire population versus age, gender, or race specific
Rely on Public Health Professionals to:
• Contact health care providers and laboratories to obtain missing data;
• Interpret laboratory tests;
• Make judgments about epidemiological linkages;
• Identify or correct mistakes in data entry; and
• Determine if epidemics are in progress.
Surveillance Data
Descriptive Epidemiology
Person, Place, and Time
Person: What are the patterns of a disease among different populations?
Place: What are the patterns of a disease in different geographic locations?
Time: What are the patterns of a disease when compared at different times (e.g., by month, year, decade) ?
5000
10000
15000
20000
25000
30000
1992
1994
1996
1998
2000
2002
# o
f c
as
es
US born
Foreign born
Overall
Tuberculosis Cases: United States 1992 - 2002
Source: http://www.cdc.gov/epo/dphsi/annsum/2002/02graphs.htm
Raw Numbers versus Rates
Ratio
A ratio is any [fraction] obtained by dividing one quantity by another; the numerator and denominator are distinct quantities, and neither is a subset of the other.
- Teutsch and Churchill (1994).
Rates, Proportions, and Percentages are all some form of a Ratio.
What Do Rates Do?
• Measures the frequency of an event over a period of time
• Includes a numerator (e.g., disease frequency for a period of time) and a denominator (e.g., population)
Why Use Rates?
Rates provide frequency measures within the context of the population.
Raw Surveillance Data
Total
Population
Crude
Rate X 104
City A 10 1,000 .01 100 per 10,000
City B 10 1,000,000 .00001 .1 per 10,000
Crude versus Specific Rates
Crude Rate: Rate calculated for the total population
Specific Rate: Rate calculated for a sub-set of the population (e.g., race, gender, age)
Rate Numerator:VA Reportable Disease
Surveillance Data
Office of Epidemiology, Virginia Department of Health
http://www.vdh.state.va.us/epi/survdata.asp
Call: (804) 864 – 8141Email: epi-comments@vdh.state.va.us
Rate Denominator:U.S. Census Data
1. http://www.census.gov2. Click on the “State & County Quick Facts” hyperlink
• Choose VA in the dropdown menu and click on GO
3. Click on the “Browse Data Sets for Virginia” hyperlink at the top of the Quick Facts data table
4. Click on the “Virginia Counties” hyperlink for ‘Population by Race and Hispanic or Latino Origin’
5. Open a new, blank file in Microsoft Excel6. Highlight table cells on the Census web page, click
CTRL + C to copy data, then paste into the same number of cells in the Excel spreadsheet
7. Name / save the Excel file in the Epi2000 folder on your c:\ drive
Import Data from Microsoft Excel or Access into
Epi Info
“Read / Import” Command
“Read / Import” Dialogue Window
Import files from alternativeSoftware programs
Import Restrictions forMicrosoft Excel Files
There can be no spaces in either the Excel file name or the column and row header cells, or sheet names within an Excel file. You can, however, have spaces in other file names in the directory path.
These three components of an Excel file cannot contain characters (e.g., #, @, !)
The Excel file cannot contain any duplicate field names.
The Excel file must be saved in the path: c:\Epi2000 folder – NOT the c:\Epi_Info folder that tends to operate as the default folder for Epi Info files.
Import Restrictions forMicrosoft Access Files
There can be no spaces in either the file name or the table or form names within an Access file. You can, however, have spaces in other file names in the directory path.
These file components cannot contain characters (e.g., #, @, !)
The Access file must be saved in the path: c:\Epi2000 OR c:\Epi_Info folder.
Online Epi Info Training
“Importing and Exporting Data Tables”
http://www.sph.unc.edu/nccphp/training/all_trainings/at_epi_info.htm
Analyze Surveillance Data
Sample Analyses
1. Time trend graph of NC data over ten years, by year for Salmonella cases
Raw data Rates
2. Maps of Salmonella rates by county: 2000 Raw Data versus Rates Choropleth
Graph Surveillance Data
Line Graph: Raw Data
Line Graph: Rate Data
Archived U.S. Census Population Estimates
http://www.census.gov/popest/archives/1990s/
– National– State– County
Estimates: present and past
Projections: future
Line Graph
Raw Data Rates
Generating a Line Graph:Considerations
• Use an x-axis scale to show a trend over time
• Select an interval size that contains enough detail for the purpose of the graph
• Label x- and y-axes
Map Surveillance Data
Epi Map Instruction
“Generating Maps”
http://www.sph.unc.edu/nccphp/training/all_trainings/at_epi_info.htm
Raw Data Map
North Carolina Salmonella Cases by County: 2002
Data source: NC Communicable Disease Data by county for 2000, General
Communicable Disease Control Branch, Epidemiology Section, Division of Public Health
Choropleth Map
North Carolina Salmonella Cases by County: 2002
Data source: NC Communicable Disease Data by county for 2000, General Communicable Disease Control Branch, Epidemiology Section, Division of Public Health
Choropleth Map
North Carolina Salmonella Rates by County: 2002
Rate numerators: NC Communicable Disease Data for 2000
Rate denominators: U.S. Census population data, by county, for 2000
Raw Data
Rates
Data Interpretation:Considerations
• Underreporting
• Inconsistent Case Definitions
• Has reporting protocol changed?
• Has the case definition changed?
• Have new providers or geographic regions entered the surveillance system?
• Has a new intervention (e.g., screening or vaccine) been introduced?
Online Surveillance Trainings
NC Center for Public Health Preparedness
http://www.sph.unc.edu/nccphp/training/training_list/t_surv.htm
Direct link to 13 surveillance trainings
Question & AnswerOpportunity
Session SummarySurveillance is the ongoing systematic collection, analysis, and interpretation of health data, essential to the planning, implementation, and evaluation of public health practice, closely integrated with the timely dissemination to those who need to know.
There are three broad forms of surveillance: passive, active, and syndromic. Passive and active differ primarily in the way in which data are reported to local health departments from health care providers, but both document confirmed cases. Syndromic surveillance involves collecting and analyzing real-time indicators for disease in an effort to identify an outbreak earlier than a traditional surveillance system will; however, cases are not confirmed via one standardized, case definition.
Session Summary
Surveillance data have many applications, including: establishing public health priorities; aiding in determining resource allocation; assessing public health programs; determining baseline rates for detection of epidemics; and early detection of epidemics.
The uneven application or availability of technologies, combined with the reporting burden and decentralized system of paper-based reporting, are inherent limitations of surveillance. Furthermore, electronic and paper-based reporting are only reliable when reporting practices are standardized and public health professionals and practitioners are trained in surveillance protocol and public health laws.
Session Summary
Federal and state or local surveillance go hand-in-hand; they are the result of a collaborative, reciprocal pathway for data collection and reporting.
When analyzing and interpreting surveillance data, it is advisable to graph rates versus raw data. It is also advisable to investigate broad, total population rates prior to evaluating specific rates for population strata such as race or gender.
Session IV Slides
Following this program, please visit the Web site below to access and download a copy of today’s slides if you have not already done so:
http://www.vdh.virginia.gov/EPR/Training.asp
Don’t Forget!
Please submit your site sign-in sheet and session evaluation forms to:
Suzi SilversteinDirector, Education and Training
Emergency Preparedness & Response Programs
FAX: (804) 225 - 3888
Next Session: May 5th
Final Session in this 5-part Series
“Epidemiology Specialties Applied”
• Disaster
• Environmental
• Forensic
References and Resources•Bonetti, M. et al (August 2003). Syndromic Surveillance PowerPoint Presentation. Harvard Center for Public Health Preparedness.
•CDC case definitions
http://www.cdc.gov/epo/dphsi/casedef/case_definitions.htm
•CDC infectious disease surveillance systems
http://www.cdc.gov/ncidod/osr/site/surv_resources/surv_sys.htm
•CDC Integrated project: National electronic diseases surveillance system
http://www.cdc.gov/od/hissb/act_int.htm
References and Resources
• CDC nationally notifiable infectious diseases http://www.cdc.gov/epo/dphsi/phs/infdis2004.htm
• CDC Notifiable diseases/deaths in selected cities weekly information. MMWR. June 4, 2004/53(21); 460-468 http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5321md.htm .
• CDC Division of Public Health Surveillance and Informatics, Epidemiology Program Officehttp://www.cdc.gov/epo/dphsi
• General Communicable Disease Control Branch, Epidemiology Section, Division of Public Health, NC Department of Health and Human Services. Reportable Communicable Diseases – North Carolina.
References and Resources• Klein, R. and Schoenborn, C. (January 2001). Age Adjustment Using the
2000 Projected U.S. Population. Healthy People 2010 Statistical Notes: No. 20. National Center for Health Statistics, Centers for Disease Control and Prevention.
• Last, J.M. (1988). A Dictionary of Epidemiology, Second Edition. New York: Oxford University Press.
• Teutsch, S. and Churchill, R. (1994). Principles and Practice of Public Health Surveillance. New York: Oxford University Press.
• U.S. Department of the Interior, U.S. Geological Survey (January 19, 2005). http://westnilemaps.usgs.gov/background.html
• Virginia Department of Health Web site: http://www.vdh.state.va.us
References and Resources
• NC Center for Public Health Preparedness Surveillance Trainings:http://www.sph.unc.edu/nccphp/training/training_list/t_surv.htm
“Surveillance”“Utilizing Infectious Disease Surveillance Data”“Acute Disease Surveillance and Outbreak
Investigation”“Syndromic Surveillance in North Carolina, 2003”“North Carolina Communicable Disease Law”“Introduction to Surveillance”“Communicable Disease Surveillance in North
Carolina”
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