midamerica center for public health practice - …states in several state and local health...
TRANSCRIPT
Enhanced Surveillance Methods and Applications:
A Local PerspectiveDani Arnold, M.S.
Bioterrorism/Infectious Disease EpidemiologistWinnebago County Health Department
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).
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.
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
Effective Treatment Period
Gain of 2 days
Early Detection Traditional DiseaseDetection
Phase IIAcute Illness
Phase IInitial Symptoms
Need for Early Detection
Source: http://www.cs.umbc.edu
Syndromic Surveillance Systems
Santa Clara County Public Health Department
Syndromal Surveillance Tally Sheet
Santa Clara County’s Tally SheetE a r ly W a r n in g S y s te m
S y n d r o m a l S u r v e illa n c e T a lly S h e e t F a c ili ty : _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ D a te : _ _ /_ _ /_ _ S h if t (c h e c k o n e ): D a y s
E v e n in g s N ig h ts
F o r e a c h p a tie n t th a t y o u e v a lu a te in tr ia g e , p le a se re c o rd w h e th e r th e y fa ll in to o n e (o r m o re ) o f th e c a te g o rie s l is te d b e lo w , o r “n o n e o f th e a b o v e .” A t th e e n d o f th e sh if t e n te r th e to ta ls a n d fa x th e in fo rm a tio n to 4 0 8 -8 8 5 -3 7 0 9 . T h a n k y o u fo r y o u r c o o p e ra tio n .
S y n d r o m e T a lly S h if t to ta l F lu - lik e sy m p to m s
F e v e r w ith m e n ta l s ta tu s c h a n g e
F e v e r w ith sk in ra sh
D ia rrh e a w ith d e h y d ra tio n
V isu a l o r sw a llo w in g d iff ic u lt ie s , d ro o p in g e y e lid s , s lu rre d sp e e c h o r d ry m o u th
A c u te re sp ira to ry d is tre s s
E x p o su re to “su sp ic io u s” i te m /su b s ta n c e
N o n e o f th e a b o v e
F A X to 4 0 8 .8 8 5 .3 7 0 9 S ig n a tu r e _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
Santa Clara County Public Health Department
• 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 emailed to the communicable disease officer for Santa Clara County
Syndromal Surveillance Tally Sheet
RODS
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 NEDSS-compliant detection systems offered for free to qualified public health departments
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
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.
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.
Real-time Outbreak Detection System (RODS)
EARS
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
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
EARS
• Allows for selection of validated aberration detection methods
• Can be used with any data source
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 2000– 2001 Super Bowl – 2001 World Series
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
EARS• Long-term surveillance
– Lasts longer than 30 days
• Short-term surveillance– “Drop-in” surveillance– Large public events
Challenges Confronting Syndromic Surveillance
Questions to Answer
Reingold A. If syndromic surveillance is the answer, what is thequestion? Biosecurity and Bioterrorism: Biodefense Strategy, Practice, and Science 2003; 1(2): 1-5.
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
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
Challenges of Implementation
Challenges of Implementation
• Resource Utilization
• User Acceptance
• Technological consideration– Constraints– Opportunities
Methodology Questions• How to differentiate from similar non-
bio-weapon illnesses?
• How does choice of elements correspond to sensitivity and specificity of model?
• How can you model probability abstractions?
Winnebago County Health Department System: BEANS
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 large-scale bioterrorism events in Winnebago County where Category A agents are disseminated
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
Agents Targeted by Surveillance System• Anthrax• Bacterial gastroenteritis• Botulism• Chickenpox • Encephalitis• Measles• Plague• Sepsis• Smallpox• Tularemia• Viral hemorrhagic fever
Syndromic Surveillance System
14
Syndromic Surveillance Apparatus
B.E.A.N.S.• 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
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
What we've seen so far…Fever with Shortness of Breath
0
2
4
6
8
10
12
247
273
299
325
351 12 38 64 91 117
145
171
197
223
249
276
302
328
354 14 40 66 92 118
144
170
196
222
248
274
300
326
352 13 39
Day of the year
Num
ber o
f peo
ple
pres
entin
g w
ith C
1
C1
What we've seen so far…Diarrhea or Vomiting (age >6 years)
0
2
4
6
8
10
12
14
16
18
247
273
299
325
351 12 38 64 91 117
145
171
197
223
249
276
302
328
354 14 40 66 92 118
144
170
196
222
248
274
300
326
352 13 39
Day of the year
Num
ber o
f peo
ple
pres
entin
g w
ith C
4
C4
Percentage of all Visits to ED Triage by Syndrome
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
1 13 25 37 49 61 73 85 97 109
121
133
145
157
169
181
193
205
217
229
241
253
265
277
289
301
313
325
337
349
361
Day of the Year
Perc
ent o
f Tot
al V
olum
e
C4
What we’ve seen so far…Diarrhea or vomiting (age >6yrs)
Small food borne outbreak
Instance where there were many unrelated cases in one day
A Comparison of Pneumonia & Influenza Mortality, School Absenteeism, Visits for Pneumonia, ILI and Specified Syndromic Surveillance Rates for the 2005-2006 Influenza
Seasons
0
5
10
15
20
25
38 41 44 47 50 1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 3 6 9 12
CDC Week
Rat
e
Smoothed Pneumonia Visits Absenteeism Rate ILI Composite RatesFever w/SOB Rate Diarrhea/Vomiting (age > 6 yrs) Smoothed P&I Mortality Rate
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
Surveillance screen before adding paper cases
Surveillance screen after adding table-top paper cases
Other Surveillance Activities
• Influenza• Pneumonia• Pollen• I-NEDSS Enteric Module• School Absenteeism
Limitations
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
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
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
Recommendations
Continued efforts in: • Collection• Analysis• Interpretation• Dissemination of data, linked to
Public health practice