severe acute respiratory syndrome (sars)

Severe Acute Respiratory Syndrome (SARS)

AA Model for Preparedness for Emerging Diseases

Finding and

Filling Gaps

What is the status of “Big Gaps”• Clinical manifestations of full blown SARS• Diagnosis and therapy • Clinical spectrum• Characteristics of transmission & transmitters• Seasonality and potential geographic range• Causative agent? Any important co-factors? • Protective factors—do children provide clues?• Where did the causative agent come from?• Is there a persistent reservoir?• How about those time lags—

– Recognizing and publicizing new syndrome– Public health prevention measures

“Big Gap” Status• Clinical manifestations of full blown SARS• Diagnosis and therapy • Clinical spectrum• Characteristics of transmission & transmitters• Seasonality and potential geographic range• Causative agent? Any important co-factors? • Protective factors—do children provide clues?• Where did the causative agent come from?• Is there a persistent reservoir?• How about those time lags—

– Recognizing and publicizing new syndrome– Public health prevention measures

“Big Gap” Status• Clinical manifestations of full blown SARS• Diagnosis and therapy • Clinical spectrum• Characteristics of transmission & transmitters• Seasonality and potential geographic range• What causes it? Any important co-factors? • Protective factors—do children provide clues?• Where did the causative agent come from?• Is there a persistent reservoir?• How about those time lags—

– Recognizing and publicizing new syndrome– Public health prevention measures

Chain of TransmissionPt “ZF”

0

5

10

15

20

25

Family HCW-Hosp 1 HCW-Hosp 2Tertiary HCW-Hosp 1 Index Case

12 3*

* *

* 1st, 2nd, and 3rd hospitalizations

China (and its neighbors)

HK-Dhaka

Flights to Bangkok

BKK-DAC

“Big Gap” Status• Clinical manifestations of full blown SARS• Diagnosis and therapy • Clinical spectrum• Characteristics of transmission & transmitters• Seasonality and potential geographic range• What causes it? Any important co-factors? • Protective factors—do children provide clues?• Where did the causative agent come from?• Is there a persistent reservoir?• How about those time lags—

– Recognizing and publicizing new syndrome– Public health prevention measures

Transmission PatternGuangdong-first 1000 cases

through February

• 28% in health care workers

• 20% in family members

• 52% unknown contacts

• 5% of cases were food preparers (compared with 1% of those with typical pneumonias over the previous two years)

Food Handlers as the Original Sentinels?

Nearly 35% of the cases recognized before Feb 1, 2003 were among food handlers—many lived near “wet markets”

Ample exposure to secretions, blood, urine and feces of domesticated/bred and wild animals in Guangdong Province

Animal Market, Guangzhou

Finding the SourceLearning from By-gone Epidemics

• Legionnaires’ disease– The bacteria are everywhere, but only one source is

usually responsible for an epidemic– Can you tell me how to clean the cooling tower?

• Schistosomiasis in Malawi• E. coli 0157 outbreaks: from hamburgers to

water parks• Message: Let epidemiology guide the animal

coronavirus surveys and confirm with molecular epi/genetic studies

Epi Studies• Begin with case-control study of first 50-100 known cases in

Guangdong– Focus on

• Pets• Visits to animal markets• Animals purchased or used

– Detail interaction with animal

• Food ingested– How cooked/served/eaten

• Nested study with case food preparers and food preparer controls– Specific behaviors/functions

• Include serologic data on cases/controls• Get isolates or sequences from as many early cases as possible• Consider similar work in cases without known contacts

“Big Gap” Status• Clinical manifestations of full blown SARS• Diagnosis and therapy • Clinical spectrum• Characteristics of transmission & transmitters• Seasonality and potential geographic range• What causes it? Any important co-factors? • Protective factors—do children provide clues?• Where did the causative agent come from?• Is there a persistent reservoir?• How about those time lags—

– Recognizing and publicizing new syndrome– Public health prevention measures

Epidemics of Emerging or Known Diseases Early Recognition and Response

What is Required?• Surveillance Systems

– Hospital-based • focused on disease or known syndrome• Enough information to recognize novel clinical or

epidemiologic pattern – unusual combination of signs/symptoms– occupational clustering (may consider surveillance in sentinel

populations—i.e. health care workers

– Behavior-based• Vinegar sales would have been a clue• Antimicrobial drug sales

– Physician-based via education/networks/hotlines

Epidemics of Emerging or Known Diseases Early Recognition and Response

Surveillance Characteristics• System should be easy to participate in• Individual reporting should be electronic• Analysis should have automated capacity with built-in

pattern recognition and also flexibility for operator manipulation

• Trained personnel need to maintain and use it• Pre-established thresholds for anomalies/prepared to

respond• Teams trained, ready, and available to investigate• International support/trust• Prepared for communication/education

VietnamSingapore

Toronto

63 cases205 cases

142 cases

Global Spread of a Novel Pathogen

Hong Kong1500 cases

Guangdong1500 cases

Big Lesson from SARSPolitical Will Required to Support, Enhance

and Utilize Public Health Infrastructure• Need for quick, transparent steps to declare presence of

lethal pathogen with borders• Intensify surveillance and report results• Use contact tracing, quarantine, and border control

measures when needed• Apply stringent infection control measures in health care

settings when indicated• Provide public with timely information

• Magnitude• Known risks• How one can protect himself/herself and family

• International public health enforcement??

Keep Some Perspective

• 5,000 cases in China—population 1.3 billion• 8,000 cases globally• Not easy to get SARS• Not the greatest health problem faced, but a

test for our preparedness to respond to public health crises

• We can use this experience to improve ourselves

May the Lord grant me a sword and no need to use it.           --Czech Proverb

Politics and Public Health