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Coronavirus, novel strains

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including Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS)

Reporting Obligations

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

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Aetiologic Agent

Coronaviruses are large, enveloped ribonucleic acid (RNA) viruses named after their corona- or crown-like surface projections observed on electron microscopy. A novel coronavirus is a new strain that has not been previously identified in humans. Coronaviruses are zoonotic, as they transmit between animals and people. There are at least seven known coronaviruses that infect humans.

Coronaviruses are a large family of viruses, some causing illness in people and others that circulate among animals, including camels, cats and bats. Rarely, animal coronaviruses can evolve and infect people and then spread between people such as has been seen with MERS (Middle East Respiratory Syndrome) and SARS (Severe Acute Respiratory Syndrome). Past MERS and SARS outbreaks have been complex, requiring comprehensive public health responses.

Clinical Presentation

Clinically compatible signs and symptoms may vary by novel coronavirus. Common signs include fever, and respiratory symptoms such as cough, shortness of breath, and breathing difficulties. In more severe cases, infection can cause pneumonia, acute respiratory distress syndrome (ARDS), severe influenza-like illness, kidney failure and even death.

Modes of Transmission

Coronaviruses are a large family of viruses that are transmitted primarily through droplets and direct contact. They are generally not airborne unless through an aerosolizing procedure. Some cause illness in people; numerous other coronaviruses circulate among animals, including camels, cats, and bats. Rarely, animal coronaviruses can evolve and infect people and then spread between people such as has been seen with Middle Eastern Respiratory Syndrome (MERS-CoV).

Incubation Period

The average incubation period for seasonal human coronavirus infections is 2 days (range of 12 hours–5 days). Novel coronaviruses have longer incubation periods. The SARS coronavirus demonstrated a prolonged incubation period (median 4–5 days; range of 2–10 days) and the incubation period for the MERS coronavirus is also prolonged at approximately 5 days (range of 2–14 days).

Allowing for variability and recall error, exposure history based on the prior 14 days is recommended at this time for novel coronaviruses with an unknown incubation period.

Period of Communicability

Not completely understood and varies by type of coronavirus.

Risk Factors/Susceptibility

Risk Factors:

  • Travel outside province in the last 14 days to an area with known cases
  • Close contact with case
  • Occupational—lab worker, healthcare worker, contact with animals or animal products
  • Chronic illness/underlying medical condition including diabetes

Susceptibility: Unknown, but susceptibility is assumed to be universal. Complications are more common in immunocompromised people and those with underlying chronic illness.

Diagnosis and Laboratory Testing

For information on testing guidelines for novel coronavirus, contact the Public Health Ontario Laboratory, or refer to the Public Health Ontario Laboratory Services webpage. PHO Laboratory’s Customer Service Centre at 416-235-6556/1-877-604-4567 or the After-Hours Emergency Duty Officer at 416-605-3113.

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Treatment and Case Management

  • Since there is no vaccine against coronaviruses the most effective measure is to prevent transmission from infected persons to susceptible persons;
  • All individuals presenting to a health care facility with symptoms of an acute respiratory infection should be provided with a surgical face mask and receive information about the importance of respiratory etiquette and hand hygiene; and
  • Ensure early recognition and prevention of transmission of novel coronaviruses and other respiratory viruses at the initial encounter with a health care facility.

Additional Resources

Guidance for Health Care Workers and Health Sector Employers

COVID‑19 Health Sector Guidance |

Public Health Ontario Laboratories testing information: Coronavirus Disease 2019 (COVID-19); MERS CoV; SARS

Public Health Agency of Canada, Travel Health Notices

COVID-19: How to Self-Isolate (


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