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Severe Acute Respiratory Syndrome (SARS)

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Reporting Obligations

Confirmed and suspect cases shall be reported by phone immediately to the local Health Unit.

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Aetiologic Agent

SARS is caused by a coronavirus similar on electron microscopy to animal coronaviruses; large, enveloped RNA viruses.

Clinical Presentation

Early signs and symptoms of SARS are nonspecific and consistent with influenza-like illness. Most common initial symptoms include a fever greater than 38°C (100.4°F), often accompanied by myalgia, malaise, chills, a non-productive cough, and rigor. After 2 to 7 days, this is followed by respiratory symptoms such as a dry cough, shortness of breath, difficulty breathing or hypoxia. In some cases, the respiratory symptoms become increasingly severe, and patients require oxygen support and mechanical ventilation.

Similar to other cases of atypical pneumonia, physical signs upon chest examination are minimal compared with radiological findings, which typically show ground-glass opacities and focal consolidations. Diarrhea is the most common extra-pulmonary manifestation.

Cases can become severe quickly, progressing to respiratory distress coinciding with peak viraemia that occurs during the second week of illness (e.g., 10 days). Nearly all confirmed infected adult cases developed pneumonia or acute respiratory distress syndrome.

Modes of Transmission

SARS is transmitted from person to person by close contact (i.e. within 2 metres) with infectious respiratory secretions or body fluids of a suspected case of SARS.

The SARS virus is thought to be transmitted most readily through respiratory droplets produced when an infected individual coughs or sneezes and possibly through fomites (inanimate objects including surfaces or objects contaminated with infectious droplets).

Incubation Period

2–10 days (mean 5 days), with isolated reports of longer incubation periods.

Period of Communicability

Not yet completely understood. Initial studies suggest that transmission does not occur before onset of clinical signs and symptoms and that maximum period of communicability is less than 21 days.

Risk Factors/Susceptibility

Unknown but susceptibility is assumed to be universal.

  • Travel outside province in the last 10 days to an area with known cases
  • Close contact with case
  • Occupational—lab worker
  • Chronic illness/underlying medical condition including diabetes

Diagnosis and Laboratory Testing

Laboratory evidence of SARS-associated coronavirus (SARS-CoV) infection; early presentation of clinically compatible signs and symptoms of SARS (fever > 38 degrees Celsius, cough or breathing difficulty, radiographic evidence is characterized by radiographic evidence of infiltrates consistent with pneumonia or ARI).

If SARS Coronavirus is suspected contact the Public Health Ontario laboratory immediately to consult with a microbiologist. Testing is not routinely available in Canada. If the travel history and clinical presentation raise suspicion of SARS testing may be available through special request at the National Microbiology Laboratory (NML) after approval by PHOL and NML microbiologists.

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Treatment and Case Management

While receiving institutional health care, SARS-infected cases should be placed on “droplet/contact precautions”. Appropriate PPE should be worn and appropriate personal protective measures performed (e.g. hand hygiene) by health care workers caring for patients infected with SARS.

Cases should not go to work, school, or other public areas until 10 days after fever and respiratory symptoms have resolved. During this time, infection prevention and control precautions for SARS patients should be followed.

Refer to the PHAC document, Public Health Management of SARS Cases and Contacts Interim Guidelines.

Contacts will be identified and followed by Public Health staff to provide management of asymptomatic and symptomatic contacts. It will be stressed to the contact that fever is usually the first symptom.

Additional Resources

Heymann, D.L. Control of Communicable Disease Manual (19th Ed.). Washington, American Public Health Association, 2008.

Public Health Agency of Canada. “Public Health Management of SARS Cases and Contacts Interim Guidelines, 2003.”


Ministry of Health and Long-Term Care, Infectious Diseases Protocol, 2022.