Disease surveillance

1. What’s New in Surveillance
Dona Schneider, PhD, MPH

2.  Surveillance 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 feedback of these data to those who
need to know. Centers for Disease Control
Examples:
Morbidity and Mortality Weekly Report (MMWR)
Disease Registries

3. Surveillance for communicable
diseases remains important…
 The world population is highly
mobile
 International travel and troop
movements increase the risk of
communicable disease
transmission
 Migration for war and famine,
and voluntary immigration
increase communicable disease
risk
 Naturally occurring disease is
not our only threat

4. Types of Surveillance
 Passive
 Inexpensive, provider-initiated
 Good for monitoring large numbers of typical health events
 Under-reporting is a problem
 Active
 More expensive, Health Department-initiated
 Good for detecting small numbers of unusual health events
 Enhanced
 Rapid reporting and communication between surveillance
agencies and stakeholders
 Best for detecting outbreaks and potentially severe public
health problems

5. New and complex disease entities
must also be monitored…
 New syndromes may emerge
that present in an atypical
manner
 Syndromic surveillance uses
health-related data that
precede diagnosis and signal
a sufficient probability of a
case or an outbreak to
warrant further public health
response

6.  Day 1- feels fine
 Day 2- headaches, fever - buys Tylenol
 Day 3- develops cough - calls nurse hotline
 Day 4- Sees private doctor – dx with “flu”
 Day 5- Worsens - calls ambulance seen in ED
 Day 6- Admitted - “pneumonia”
 Day 7- Critically ill - ICU
 Day 8- Expires - “respiratory failure”
 Case enters surveillance system through an EDC
Example of Passive Surveillance

7.  Day 1- feels fine
 Day 2- headaches, fever - buys Tylenol
 Day 3- develops cough - calls nurse hotline
 Day 4- Sees private doctor - dx “flu”
 Day 5- Worsens - calls ambulance - seen in ED
 Day 6- Admitted - “pneumonia”
 Day 7- Critically ill - ICU
 Day 8- Expires - “respiratory failure”
 Case is under immediate investigation by the LHD
because of the pre-diagnostic information gathered
Pharmaceutical Sales
Nurse’s Hotline
Managed Care Org
Ambulance Dispatch (EMS)
ED Logs
Absenteeism records
Example of Syndromic Surveillance

8. We also watch for sentinel events…
 Sentinel surveillance
identifies preventable
disease, disability, or deaths
that warn that known
methods of prevention,
treatment or safety need to
be improved
 Sentinel events may have
catastrophic outcomes – they
may indicate the “tip of the
iceberg”

9. Sentinel Surveillance
 Monitors
 Sites
 Events
 Providers
 Vectors/animals

10. SENTINEL EVENT
Nov 12, 2001 - 9:17 am
Flight AA 587 Crashes in Rockaways
7-Zip Surveillance showed:
27 Obs / 10 Exp Resp Emergencies
p<0.001
31 Obs / 16 Exp Hospital Events
p<0.05

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Date
Resp/None
Syndromes
Rockaways
Rest of City

12. Investigation
 Key Questions
 True increase or natural variability?
 Bioterrorism or self-limited illness?
 Available Methods
 Response team assigned
 Response team “Drills down”
 Query clinicians / laboratories
 Chart reviews
 Patient follow-up
 Increased diagnostic testing

13. Investigation
 Chart review in one hospital (9 cases)
 Smoke Inhalation (1 case)
 Atypical Chest Pain / Anxious (2 cases)
 Shortness of Breath - Psychiatric (1 case)
 Asthma Exacerbation (3 cases)
 URI/LRI (2 cases)
 Checked same-day logs at 2 hospitals
Increase not sustained

14. Surveillance can…
 Estimate the magnitude of a problem
 Determine geographic distribution of illness
 Detect epidemics/outbreaks
 Generate hypotheses, stimulate research
 Evaluate control measures
 Monitor changes in infectious agents
 Detect changes in health practices
0
5
10
15
20
25
30
TIME
CASES

15. Data Sources
 Notifiable diseases
 Laboratory specimens
 Vital records
 Sentinel surveillance
 Registries and surveys
 Administrative data systems
 Other data sources

16. Reported Cases of Food borne Botulism,
United States, 1981-2001
*Data from annual survey of State Epidemiologists and Directors of State Public Health Laboratories.
Source: CDC. Summary of notifiable diseases. 2001.

17. Cases of Measles
United States, 1966-2001
Source: CDC. Summary of notifiable diseases. 2001.

18. Blood Lead Measurements 1975-1981
1975 1976 1977 1978 1979 1980 1981
30
40
50
60
70
80
90
100
110
8
10
12
14
16
18
Year
Predicted blood lead
Gasoline lead
Observed blood lead
Source: Pirkle et al JAMA 272:284-91, 1994
Lead used
in
gasoline
(thousands
of tons)
Mean
blood
lead
levels
 g/dl

19. Reported Salmonella Isolates,*
United States, 1976-2001
*Data from Public Health Laboratory Information System (PHLIS).
Source: CDC. Summary of notifiable diseases. 2001.

20. National Notifiable Diseases Surveillance
System (NNDSS) – produces the data in the
MMWR
 The reportable diseases list is revised periodically
by the CSTE/CDC
 States report diseases to the CDC voluntarily
 Reporting is mandated at the state level
 All states report the internationally quarantinable
diseases (i.e., cholera, plague, SARS, smallpox
and yellow fever) in compliance with WHO
International Health Regulations and a varied list
of other diseases

21. In New Jersey
 Reporting mandated by state law/regulation
 Health care providers, laboratories report to the
LHD (county)
 LHD submits reports to the State
 Reports transmitted by State to CDC primarily
through National Electronic Telecommunications
System for Surveillance (NETSS)

22. Other NCHS Data Systems for
Surveillance
Vital Statistics
 National Infant Mortality Surveillance (NIMS)
 Linked:
• birth records
• death records

23. SENSOR
Sentinel
Event
Notification
System for
Occupational
Risks

24. Recent Occupational Monitoring
Efforts for Sentinel Events Include…
 Biodetection Systems (BDS) in NJ post
offices to detect anthrax and soon, ricin
 Biowatch, an air monitoring system in New
York City and 30 other cities

25. Weekly Communicable Disease
Reporting System (CDRS) Alerts
 Comparison of current 4-week reporting
period to previous reporting periods;
generated at NJDHSS every Monday
 by disease
 by county
 Increase over baseline (3 SD) triggers an
alert for further investigation
 Limitation: timeliness of reporting into
CDRS

26. County Disease
Cum
Reports
Baseline
4-wk Av SD
Last 4-
wk
Period Flag
Amebiasis (Entamoeba histolytica) 211 5.5 4.6 8
√
Campylobacteriosis (Campylobacter
spp)
1,296 40.6 17.6 28
√
Creutzfeld-Jakob disease 21 1.0 0.0 1
Cryptosporidiosis (Cryptosporidium
spp.)
52 1.8 0.8 1
Encephalitis, West Nile 42 5.6 4.3 2
√
Enterohemorrhagic E. coli O157:H7 171 7.1 4.5 3
√
Giardiasis (Giardia lamblia) 1,427 51.9 9.9 21
√
Haemophilus influenzae - invasive
disease
167 4.3 1.9 1

27. County ZIP Category Sale
Base
Mean
Date 1
Sales in
Date 1
Base
Mean
Date 2
Sales in
Date 2
Base
Mean
Date 3
Sales in
Date 3
Diarrhea N 3.9 8 (03/11/03) 3.6 4 (03/12/03) 5.3 11 (03/13/03)
Antifever N 12.4 6 (03/11/03) 11.4 9 (03/12/03) 10.0 20 (03/13/03)
Diarrhea N 2.7 3 (03/11/03) 3.5 3 (03/12/03) 3.6 8 (03/13/03)
Cough/Cold N 35.7 30 (03/10/03) 37.8 30 (03/11/03) 18.6 53 (03/12/03)
Cough/Cold N 44.0 42 (03/10/03) 52.7 45 (03/11/03) 27.0 72 (03/12/03)
Cough/Cold N 192.6 178 (03/11/03) 193.3 181 (03/12/03) 167.3 191 (03/13/03)
Hydrocort-
isones
N 2.5 1 (03/10/03) 2.1 2 (03/11/03) 1.7 6 (03/12/03)
Cough N 11.3 14 (03/11/03) 7.7 13 (03/12/03) 11.3 15 (03/13/03)
Antifever Y 9.3 9 (03/11/03) 5.1 4 (03/12/03) 3.9 13 (03/13/03)
Antifever Y 8.8 11 (03/11/03) 7.7 8 (03/12/03) 5.7 20 (03/13/03)
New Jersey Real Time Outbreak and Disease Surveillance (RODS)
OTC Surveillance
Reports Through March 15, 2003

28. Cipro and Doxycycline
Prescriptions
0
50000
100000
150000
200000
250000
7/1/2001 7/29/2001 8/26/2001 9/23/2001 10/21/2001 11/18/2001 12/16/2001 1/13/2002
0
5000
10000
15000
20000
25000
30000
35000
40000
Cipro Doxycycline
9/11
First anthrax case
reported, 10/4/01.
CDC recommends
doxycyline 10/28/01.

29. Tobacco Cessation Aids Sold at a Large
Pharmacy Chain
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2
Week Ending
Units
per
100,000
prescriptions $0.39
increase in
State tax
$1.42
increase
in City
tax

30. National Electronic Disease
Surveillance System (NEDSS)
 Will replace NETSS, HIV/AIDS, TB, STD,
vaccine-preventable and infectious
disease reporting systems
 Goal is to standardize health reporting and
link laboratory, hospital and managed care
data

31. Enhanced and Syndromic Surveillance
 Costs
 Implementation costs are modest
 Operational costs = time of public health staff,
investigations
 Benefits
 Possibily huge if early detection results
 Strengthens traditional surveillance
 Sets high standards for all data collection agencies

32. Good surveillance does not necessarily ensure
the making of right decisions, but it reduces the
chances of wrong ones.
Alexander D. Langmuir
NEJM 1963;268:182-191

33. Free Resources
World Health Organization
DISMOD Software
Centers for Disease Control
Epi Info