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

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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

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Rockaways

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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

Cipro and Doxycycline Prescriptions

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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

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Predicted blood lead

Gasoline lead

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Source: Pirkle et al JAMA 272:284-91, 1994

Lead used in gasoline(thousan

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Mean bloodlead

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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.

Tobacco Cessation Aids Sold at a Large Pharmacy Chain

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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

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