Surveillance and Notification of Diseases

SURVEILLANCE AND NOTIFICATION OF DISEASES Ghaiath M.A. Hussein MBBS, MHSc. (Bioethics)

Outline of presentation What is surveillance? What are the objectives of surveillance? How to establish/run an effective surveillance system? Challenges to effective surveillance Key messages Ghaiath Surveillance (JPFCM, Jan. 2010)

What is an epidemiological surveillance system? The systematic collection, analysis, interpretation, and dissemination of health data on an ongoing basis, to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community. Epidemiological surveillance is a process of watchfulness over health events which may occur in a population. A set of interconnected elements and activities that are usually established as an integral part of a health care system in order to monitor priority health events. Ghaiath Surveillance (JPFCM, Jan. 2010)

Surveillance: General principle Health Care System Public Health Authority Data Information Decision Action Feedback Reporting Evaluation Analysis & Interpretation Ghaiath Surveillance (JPFCM, Jan. 2010)

“ Public Health Surveillance” Ghaiath Page 5 of 19 Describes the scope (surveillance) Indicates the context in which the event occurs (public health) Surveillance (JPFCM, Jan. 2010)

Task oriented approach to Communicable Disease Surveillance and Control P P P P P P I I C World Health Organisation Regional Offices + HQ P = peripheral level I = intermediate level C = central Level Detect Treat Report Analyse Investigate Report Respond Feedback Analysis and feedback Support Policy and targets Funding Analyse Investigate Confirm Respond Plan and Fund Feedback Ghaiath Surveillance (JPFCM, Jan. 2010)

Elements of Surveillance Ghaiath Page 7 of 19 Collection Analysis Interpretation Dissemination Surveillance (JPFCM, Jan. 2010)

Components of Public Health Practice Ghaiath Page 8 of 19 Surveillance Research: epidemiological, behavioral, and laboratory Service (program evaluation) Training Surveillance (JPFCM, Jan. 2010)

Purposes of Public Health Surveillance Data Ghaiath Page 9 of 19 Assess status Define position Monitor and evaluate programs Conduct research Identify problems Surveillance (JPFCM, Jan. 2010)

Comparing the number of confirmed dengue fever cases by International weeks 2006-2009 Ghaiath Surveillance (JPFCM, Jan. 2010)

Confirmed dengue fever cases up to 31st International week 2006-2009 Ghaiath Surveillance (JPFCM, Jan. 2010)

المرحلة الأولى 32000 منزل ( محرم - صفر ) المرحلة الثانية 130000 منزل ( ربيع الأول حتى تاريخه ) Ghaiath Surveillance (JPFCM, Jan. 2010)

Steps in Planning Surveillance 1. Establish objectives 2. Develop case definitions 3. Develop data collection system 4. Develop data collection instruments 5. Field test methods 6. Develop data analysis approach 7. Determine dissemination mechanism 8. Determine evaluation method Page 13 of 24 Ghaiath Surveillance (JPFCM, Jan. 2010)

Which condition to surveillance? Page 14 of 24 Criteria for Determining High-Priority Events Frequency Severity Direct and indirect costs Preventability Communicability Public interest Emerging issues Consensus process Ghaiath Surveillance (JPFCM, Jan. 2010)

Elements of a Case Definition Page 15 of 24 Criteria for time, place, and person Clinical and laboratory diagnosis Epidemiological features of disease Degree of certainty regarding diagnosis High sensitivity and specificity Ghaiath Surveillance (JPFCM, Jan. 2010)

Data Collection Ghaiath Surveillance (JPFCM, Jan. 2010)

Determining Data Collection Systems Page 17 of 24 Methods of data collection Balance between system and its purpose Timeliness Type of condition Need for lab-based information Ghaiath Surveillance (JPFCM, Jan. 2010)

Types of Data Collection Systems Page 18 of 24 Vital records system Existing data sets Existing registries or surveys Ghaiath Surveillance (JPFCM, Jan. 2010)

Passive Systems Page 19 of 24 Simple Less burdensome Limited by variability May not be representative May fail to identify outbreaks Portray trends Ghaiath Surveillance (JPFCM, Jan. 2010)

Active Systems Page 20 of 24 Validate representativeness Assure more complete reporting Can be used with specific investigations Can be used for brief periods Ghaiath Surveillance (JPFCM, Jan. 2010)

Uses of Limited Surveillance Systems Page 21 of 24 Resolve specific problems Identify all cases Use for logistic or economic reasons Ghaiath Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 22 of 27 Sentinel Surveillance Encompasses a wide range of activities focused on monitoring key health indicators in general or in special populations Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 23 of 27 Sentinel refers to Key health events Clinics or other sites at which health events are monitored Reporters who report specific health events Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 24 of 27 Sentinel Sites Hospitals Clinics Counties Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 25 of 27 Role of Sentinel Sites Monitor conditions for which information is not otherwise available Monitor conditions in subgroups which are more vulnerable than general population Surveillance (JPFCM, Jan. 2010)

Analysis and Interpretation of surveillance data Ghaiath Surveillance (JPFCM, Jan. 2010)

Considerations in Analysis of Surveillance Data Ghaiath Page 27 of 79 Know inherent idiosyncrasies of data set Proceed from simplest to most complex Realize when inaccuracies in data preclude more sophisticated analyses Surveillance (JPFCM, Jan. 2010)

Key Concepts that Determine Accuracy of Surveillance Data Reliability : Is a particular condition reported consistently by different observers? Validity : Does the particular condition as reported reflect the true condition as it occurs? Ghaiath Page 28 of 79 Surveillance (JPFCM, Jan. 2010)

Basic Epidemiological Parameters Ghaiath Page 29 of 79 Time Place Person Surveillance (JPFCM, Jan. 2010)

Data Analysis by Time Ghaiath Page 30 of 79 Compare number of case reports received during a specific interval Compare number of cases for a current time period with number reported during same interval during previous time period Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 31 of 79 Surveillance (JPFCM, Jan. 2010)

Data Analysis by Place Ghaiath Page 35 of 79 Where exposure occurred, not where it’s reported from Allows prevention resources to be targeted effectively Use of computers and spatial mapping software allows for sophisticated analysis Surveillance (JPFCM, Jan. 2010)

Data Analysis by Person Ghaiath Page 37 of 79 Possible variables: age gender race or ethnicity marital status occupation levels of income and education Surveillance (JPFCM, Jan. 2010)

Interactions Among Time, Place, and Person Ghaiath Page 38 of 79 Interactions can obscure patterns of disease and injury Syphilis in the 1980s Surveillance (JPFCM, Jan. 2010)

Why Interpret and Disseminate Information? Page 39 of 24 Help decision makers understand the implications of information Facilitate consequent implementation of public health action Ghaiath Surveillance (JPFCM, Jan. 2010)

Interpretation of Information Page 40 of 24 Present information clearly Know your audience Ghaiath Surveillance (JPFCM, Jan. 2010)

Considerations for Dissemination Page 41 of 24 Balance access with privacy constraints Provide analyses and recommendations Use clear and concise materials Use communications media Use current AV technology Ghaiath Surveillance (JPFCM, Jan. 2010)

Steps in Dissemination Ghaiath Page 42 of 79 1. Use visual displays to convey structure of data and analyses 2. Transform data mathematically to simplify distribution 3. Investigate influence of outliers 4. Examine residuals Surveillance (JPFCM, Jan. 2010)

Purpose of Graphics Ghaiath Page 47 of 79 To visually display measured quantities To allow researchers to mesh presentation and analysis To organize, summarize, and display information clearly and effectively Surveillance (JPFCM, Jan. 2010)

Tables Ghaiath Page 48 of 79 Arrange data in rows and columns Demonstrate data patterns and relationships among variables Serve as a source of information for other types of data graphics Surveillance (JPFCM, Jan. 2010)

Guidelines for Developing a Table Ghaiath Page 49 of 79 Describe what, when, where in the title Label rows and columns clearly Provide units of measure Provide row and column totals Define abbreviations and symbols Note data exclusions References Source Should stand alone Surveillance (JPFCM, Jan. 2010)

بيان بعدد المواقع المستكشفة ليرقات البعوض والعدد الإيجابي بمكة المكرمة خلال شهري يناير وفبراير 2009 م اليرقات الأخرى عدد يرقات الأيدس إيجبتاي ا لأماكن الإيجابية لليرقــــات المواقـــــع المستكشفة الأسبوع الوبائي الشهـــــــر ط 1 ط 2 ط 1 ط 2 ط 3 + ط 4 ط 1 + ط 2 357 254 547 110 25 770 1 يناير 567 133 421 87 43 926 2 510 168 296 193 45 841 3 216 95 530 264 40 819 4 302 110 610 329 54 956 5 145 24 608 128 55 884 6 فبراير 646 312 599 305 13 1038 7 331 231 456 163 83 876 8 275 151 328 204 57 1118 9

Graphs Ghaiath Page 52 of 79 Visually display quantitative information Provide system of coordinates Assist reader to visualize patterns and trends Surveillance (JPFCM, Jan. 2010)

Guidelines in Developing Graphs Ghaiath Page 53 of 79 Label title, source, axes, scales, legend Minimize the number of coordinate lines Portray frequency on the vertical scale, starting with zero Portray method of classification on the horizontal scale Indicate units of measure Define abbreviations and symbols Note data exclusions Surveillance (JPFCM, Jan. 2010)

Maps Ghaiath Page 60 of 79 Graphically represent data using location and geographic coordinates Provide a clear, concise, and quick method for grasping data Surveillance (JPFCM, Jan. 2010)

المرحلة الأولى 32000 منزل ( محرم - صفر ) المرحلة الثانية 130000 منزل ( ربيع الأول حتى تاريخه )

Limitations in Data Ghaiath Page 62 of 79 Under-reporting Unrepresentativeness Inconsistent case definitions Surveillance (JPFCM, Jan. 2010)

Considerations for Interpreting Data Has nature of reporting changed? Have new providers or geographic areas entered the system? Has case definition changed? Has new intervention been introduced? Ghaiath Page 63 of 79 Surveillance (JPFCM, Jan. 2010)

Interpretive Uses for Surveillance Data Ghaiath Page 64 of 79 Monitoring trends Identifying epidemics Identifying syndrome Evaluating public policy Projecting future needs Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 65 of 27 Limitations of Reporting Systems Under reporting Incomplete reporting * If consistent surveillance methods are used, data will describe trends despite under reporting Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 66 of 27 Factors Contributing to Incomplete Reporting Concealment due to social stigma Lack of awareness of requirements Inadequate knowledge of case definitions Changes in procedures Variations in diagnosis skills Low priority Surveillance (JPFCM, Jan. 2010)

Ghaiath Page 67 of 27 Strengths of Reporting System Quick information Detect changes in patterns Detection of outbreaks Availability of information from all jurisdictions Basis for prevention recommendations Surveillance (JPFCM, Jan. 2010)

Discussion… (Qs & As) Ghaiath Surveillance (JPFCM, Jan. 2010)

references FETP series lectures on epidemiology Ghaiath Surveillance (JPFCM, Jan. 2010)

Surveillance and Notification of Diseases

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