Enhanced Surveillance Methods and Applications: A Local Perspective

Transcription

1 Enhanced Surveillance Methods and Applications: A Local Perspective Dani Arnold, M.S. Bioterrorism/Infectious Disease Epidemiologist Winnebago County Health Department

2 What is Syndromic Surveillance? The term syndromic surveillance applies to surveillance using health-related data that precede diagnosis and signal a sufficient probability of case or an outbreak to warrant further public health response, (CDC).

3 Why Syndromic Surveillance? By designing surveillance systems that target initial symptoms of disease, rather than waiting days or weeks to detect illness, steps can be taken earlier to treat ill persons and possibly prevent others from becoming ill.

4 Need for Early Detection Disease Detection Phase I Initial Symptoms Early Detection Gain of 2 days Phase II Acute Illness Traditional Disease Detection Effective Treatment Period Incubation Period (Hours) Source:

5 Syndromic Surveillance Systems

6 Santa Clara County Public Health Department Syndromal Surveillance Tally Sheet

7 Santa Clara County s Tally Sheet Early W arning System Syndrom al Surveillance Tally Sheet Facility: Date: / / Shift (check one): D ays Evenings N ights For each patient that you evaluate in triage, please record whether they fall into one (or more) of the categories listed below, or none of the above. At the end of the shift enter the totals and fax the information to Thank you for your cooperation. Syndrom e Tally Shift total Flu-like symptoms Fever with mental status change Fever with skin rash Diarrhea with dehydration Visual or swallowing difficulties, drooping eyelids, slurred speech or dry mouth Acute respiratory distress Exposure to suspicious item/substance None of the above FAX to Signature

8 Santa Clara County Public Health Department Syndromal Surveillance Tally Sheet Faxes are collected several times a day by staff who manually enter the data into a surveillance database Graphical displays of the prior days counts are manually generated and ed to the communicable disease officer for Santa Clara County

9 RODS

10 RODS Real-time Outbreak and Disease Surveillance Funding through the CDC, Defense Advanced Research Projects Agency (DARPA), and the Pennsylvania Department of Health Work is centered on development of NEDSScompliant detection systems offered for free to qualified public health departments

11 RODS Examines data routinely collected by clinical and other information systems automatically and in real-time Currently in operation in Pennsylvania and in Utah, and in the works in Chicago

12 RODS RODS software comprises three main components: 1. A Health-Level 7 (HL7) listener that receives HL7 messages in real-time through TCP/IP socket connections from hospitals Registration data is extracted from the HL7 messages and stored in a database for analysis.

13 RODS RODS software comprises three main components: (Continued) 2. A time-series detection algorithm that monitors data identifies deviations from expected levels 3. Servlets for use in web applications that generate temporal and spatial views of registration data and the results of the detection algorithm.

14 Real-time Outbreak Detection System (RODS)

15 EARS

16 EARS Early Aberration Reporting System Developed by the Centers for Disease Control and Prevention (CDC) Purpose: Provide national, state, and local health departments with several alternative aberration detection methods that have been developed for syndromic surveillance

17 EARS A group of SAS programs for data analysis Following Sept. 11 EARS was modified into a standard surveillance system for the New York City and Washington, DC Departments of Health

18 EARS Allows for selection of validated aberration detection methods Can be used with any data source

19 EARS Implemented throughout the United States in several state and local health departments and in health departments in several other countries. Used for syndromic surveillance at several large public events: Democratic National Convention of Super Bowl 2001 World Series

20 EARS Detection comprises 2 broad categories: Case definition methods Defines an event of interest tracking those syndromes considered of greatest importance Pattern recognition methods Identifies symptoms (or sets of symptoms) that deviate from an expected baseline

21 EARS Long-term surveillance Lasts longer than 30 days Short-term surveillance Drop-in surveillance Large public events

22 Challenges Confronting Syndromic Surveillance Questions to Answer Reingold A. If syndromic surveillance is the answer, what is the question? Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science 2003; 1(2): 1-5.

23 Reduce Morbidity/Mortality Following Bioterrorist Event Difficult to determine with certainty Attack must involve area under surveillance Need comparison group Easier to determine sensitivity/specificity in detecting clusters of naturally occurring illness Useful for comparing SSS, but no substitute for real-world operation

24 Detect Bioterrorist Events of Given Type/Size Must be looking for the right syndrome Size of attack must be sufficient to be detected Dependent on sensitivity of system and numbers/rates used to signal possible clusters

25 Challenges of Implementation

26 Challenges of Implementation Resource Utilization User Acceptance Technological consideration Constraints Opportunities

27 Methodology Questions How to differentiate from similar nonbio-weapon illnesses? How does choice of elements correspond to sensitivity and specificity of model? How can you model probability abstractions?

28 Winnebago County Health Department System: BEANS

29 B.E.A.N.S. B.E.A.N.S. (Bioterrorism Epidemic Advanced Notification System) System has been live for over a year and a half Designed to detect moderate to largescale bioterrorism events in Winnebago County where Category A agents are disseminated

30 Biological Agents/Diseases Category A Anthrax, botulism, plague, smallpox, tularemia, viral hemorrhagic fevers (filoviruses & arenaviruses) Category B Brucellosis, epsilon toxin of Clostridium perfringens, food safety threats, glanders, melioidosis, psittacosis, Q fever, ricin toxin, Staphylococcal enterotoxin B, typhus fever, viral encephalitis & water safety threats Category C Emerging infectious diseases such as hantavirus

31 Agents Targeted by Surveillance System Anthrax Bacterial gastroenteritis Botulism Chickenpox Encephalitis Measles Plague Sepsis Smallpox Tularemia Viral hemorrhagic fever

32 Syndromic Surveillance System Syndromic Surveillance Apparatus 14

33 Submissions are captured in real-time Minimal impact on workload for triage nurses Symptoms are detected at earliest point in patient visit enabling for early detection of outbreaks B.E.A.N.S.

34 Agents Targeted by Each Syndrome Fever with shortness of breath (C1): Smallpox, anthrax, plague, tularemia, botulism, viral hemorrhagic fever, influenza Fever with mental status change (C2): Encephalitis or sepsis Fever with either rash or blisters (C3): Smallpox, measles, chickenpox Diarrhea or vomiting (age >6yrs) (C4): Bacterial gastroenteritis Bilateral weakness (face or limbs) (C5): Botulism None of the above (C6): Captures total number of patients seen allowing for analyses both by absolute number and percent allows for better statistical comparison

35 What we've seen so far Fever with Shortness of Breath Day of the year C1 Number of people presenting with C1

36 What we've seen so far Diarrhea or Vomiting (age >6 years) Day of the year C4 Number of people presenting with C4

37 What we ve seen so far Diarrhea or vomiting (age >6yrs) Percentage of all Visits to ED Triage by Syndrome Small food borne outbreak 7.00 Percent of Total Volume Instance where there were many unrelated cases in one day C Day of the Year

38 A Comparison of Pneumonia & Influenza Mortality, School Absenteeism, Visits for Pneumonia, ILI and Specified Syndromic Surveillance Rates for the Influenza Seasons Rate CDC Week Smoothed Pneumonia Visits Absenteeism Rate ILI Composite Rates Fever w/sob Rate Diarrhea/Vomiting (age > 6 yrs) Smoothed P&I Mortality Rate

39 POD Tabletop Exercise 80 paper cases simulating patients presenting at local ERs Symptoms assessed and entered into BEANS system as though patient was being triaged at ER

40 Surveillance screen before adding paper cases

41 Surveillance screen after adding table-top paper cases

42 Other Surveillance Activities Influenza Pneumonia Pollen I-NEDSS Enteric Module School Absenteeism

43 Limitations

44 Limitations Not capturing a complete triage picture Some patients are not getting entered (i.e. ambulance bay) Relies on human input Not well integrated into hospital systems Continuous maintenance and upkeep of computer operating systems and data transferring

45 Limitations Lack of steady stream of funding Compatibility across jurisdictions Not all of these systems discussed today will work in each county; systems are chosen based on population size and community need

46 Recommendations Syndromic Surveillance will become commonplace at state and national levels within the next 5 years IDPH should facilitate local efforts to develop systems and provide guidance to ensure that State standards are met

47 Recommendations Continued efforts in: Collection Analysis Interpretation Dissemination of data, linked to Public health practice

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