Surveillance

Dona Schneider, PhD, MPH

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

Surveillance can…

Estimate the magnitude of a problem Determine geographic distribution of illness Detect epidemics/outbreaks Generate hypotheses, stimulate research Evaluate whether control measures work Monitor changes in infectious agents Detect changes in health practices

0

5

10

15

20

25

30

TIME

CA

SE

S

Examples:

Morbidity and Mortality Weekly Reporthttp://www.cdc.gov/mmwr/

SEER Cancer Registry http://seer.cancer.gov/

US Vital Statistics http://wonder.cdc.gov/welcome.html

National Notifiable Diseases Surveillance System (NNDSS) – produces the data in the

MMWR

The reportable diseases list is revised periodically by the Council of State and Territorial Epidemiologists (CSTE) and the Centers for Disease control (CDC)

States report their cases to the CDC Internationally quarantinable diseases (i.e.,

cholera, plague and yellow fever) must be reported to the World Health Organization (WHO)

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        

The Epidemic and Pandemic Alert and Response (EPR) Program at the WHO

Monitors… Anthrax Avian influenza Crimean-Congo

haemorrhagic fever (CCHF) Dengue/dengue

haemorrhagic fever Ebola haemorrhagic fever Hepatitis Influenza Lassa fever

Marburg haemorrhagic fever Meningococcal disease Plague Rift Valley fever Severe Acute Respiratory

Syndrome (SARS) Smallpox Tularaemia Yellow fever

Surveillance for communicable diseases is important…

The world population is highly mobile

International travel and troop movements increase the risk of communicable disease transmission

Forced migration for war and famine, and voluntary immigration increase communicable disease risk

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

Syndromic surveillance

Allows us to identify groups of signs and symptoms that precede diagnosis and signal a sufficient probability of a case or an outbreak that warrants a further public health response

Example: EBOLA VIRUS

Sentinel Surveillance

Monitors Sites – volcanos Events – 9/11 Providers – ERs Vectors/animals

• Rabies• West Nile

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

0

5

10

15

20

25

30

35

40

10/2

5/20

01

10/2

7/20

01

10/2

9/20

01

10/3

1/20

01

11/2

/200

1

11/4

/200

1

11/6

/200

1

11/8

/200

1

11/1

0/20

01

11/1

2/20

01

11/1

4/20

01

11/1

6/20

01

11/1

8/20

01

11/2

0/20

01

11/2

2/20

01

11/2

4/20

01

11/2

6/20

01

11/2

8/20

01

11/3

0/20

01

12/2

/200

1

12/4

/200

1

12/6

/200

1

12/8

/200

1

12/1

0/20

01

12/1

2/20

01

12/1

4/20

01

12/1

6/20

01

12/1

8/20

01

Date

Res

p/N

on

e S

ynd

rom

es

Rockaways

Rest of City

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

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.

Blood Lead Measurements 1975-1981

1975 1976 1977 1978 1979 1980 198130

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(thousan

dsof tons)

Mean bloodlead

levels g/dl

Reported Salmonella Isolates,* United States, 1976-2001

*Data from Public Health Laboratory Information System (PHLIS).

Source: CDC. Summary of notifiable diseases. 2001.

Tobacco Cessation Aids Sold at a Large Pharmacy Chain

0

50

100

150

200

250

300

350

400

Week Ending

Un

its

per

100

,000

pre

scri

pti

on

s$0.39

increase in State tax

$1.42 increase in City

tax

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

Free Resources

World Health Organization DISMOD Software http://www.who.int/healthinfo/boddismod/en/

Centers for Disease ControlEpi Info and Epi Maphttp://www.cdc.gov/epiinfo/

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