Surveillance

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Surveillance

• Dona Schneider, PhD, MPH

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• 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

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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

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Examples Morbidity and Mortality Weekly
Report http//www.cdc.gov/mmwr/ SEER Cancer
Registry http//seer.cancer.gov/ US Vital
Statistics http//wonder.cdc.gov/welcome.html
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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)

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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

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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

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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

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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

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Sentinel Surveillance

• Monitors
• Sites volcanos
• Events 9/11
• Providers ERs
• Vectors/animals
• Rabies
• West Nile

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SENTINEL EVENT Nov 12, 2001 - 917 am Flight AA
587 Crashes in Rockaways 7-Zip Surveillance
showed 27 Obs / 10 Exp Resp Emergencies
plt0.001 31 Obs / 16 Exp Hospital Events
plt0.05
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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

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Cipro and Doxycycline Prescriptions
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Blood Lead Measurements 1975-1981
110
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Predicted blood lead
100
Lead used in gasoline (thousands of tons)
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90
Mean blood lead levels ? g/dl
80
Gasoline lead
14
70
Observed blood lead
12
60
50
10
40
30
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1975
1976
1977
1978
1979
1980
1981
Year
Source Pirkle et al JAMA 272284-91, 1994
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Reported Salmonella Isolates, United States,
1976-2001
Data from Public Health Laboratory Information
System (PHLIS).
Source CDC. Summary of notifiable diseases.
2001.
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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

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Free Resources

• World Health Organization
• DISMOD Software
• http//www.who.int/healthinfo/boddismod/en/
• Centers for Disease Control
• Epi Info and Epi Map
• http//www.cdc.gov/epiinfo/

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• Good surveillance does not necessarily ensure the
  making of right decisions, but it reduces the
  chances of wrong ones.

Alexander D. Langmuir NEJM 1963268182-191