Christine L. Case, Ed.D.
Biology Professor
Skyline College

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Tracking an Outbreak

During November 1, 2002--May 23, 2003, a total of 7,956 SARS cases were reported to WHO from 28 countries (map), including the United States; 666 deaths (case-fatality proportion: 8.4%) have been reported. In the United States as of May 23, a total of 355 SARS cases were reported to CDC from 40 states. Over 300 cases have been attributed to travel exposure. Figure 1. Severe acute respiratory syndrome (SARS) is caused by a coronavirus.

See the path taken by the SARS virus.

Case definition

Suspect Case
Respiratory illness of unknown etiology with onset since February 1, 2003, and the following criteria:

  • Measured temperature greater than 100.4°F (greater than 38°C) AND
  • One or more clinical findings of respiratory illness (e.g., cough, shortness of breath, difficulty breathing, or hypoxia) AND
  • Travel within 10 days of onset of symptoms to an area with documented or suspected community transmission of SARS; excludes areas with secondary cases limited to healthcare workers or direct household contacts) OR
  • Close contact within 10 days of onset of symptoms with a person known to be a suspect SARS case.

Probable Case
A suspect case with one of the following:

  • Radiographic evidence of pneumonia or respiratory distress syndrome
  • Autopsy findings consistent with respiratory distress syndrome without an identifiable cause
The SARS virus. Coronaviruses get their name from the corona (crown) of spikes. These are made of glycoprotein. The spikes attach to a host cell. The virus has an envelope derived from the host cell. In the case of coronaviruses, this membrane is derived from inside the cell, not from the cell surface. The core consists of protein and + stranded RNA. Coronaviruses cause upper respiratory tract infections and the common cold.

 
  Data source: MMWR. April 25, 2003 / 52(16);357-360.