Severe Acute Respiratory Syndrome (SARS)

What is SARS?

Severe Acute Respiratory Syndrome is an atypical pneumonia of unknown etiology, which has recently been identified in Asia, North America and Europe. While the exact incidence of SARS is not known, it is known that SARS is contagious and fatal.

Evidence to-date indicates that close contact (e.g. household contact or care provider) with an infected person is needed for the infective agent to spread from person to person.  Close contact with aerosolized droplets and bodily fluids from an infected person appears to be important.  The amount of the infective agent needed to cause an infection has not yet been determined.

The precise nature of the agent responsible for SARS in not understood.  Currently there are several hypotheses under investigation, which include a human metapneumovirus (hMPV).

How common is it in Ontario?

Epidemiological evidence, case fatality rate, is unavailable as SARS is epidemiologically evolving worldwide.

Why is being made reportable?

Due to the risk of SARS transmission via exposure to a case, reporting of SARS is necessary to ensure that cases or suspected cases of SARS are subject to control measures which apply to communicable diseases.

SARS is a new and emerging communicable disease with an evolving epidemiology. These regulatory changes have been implemented to optimize reporting and prevention of SARS cases in a timely manner in the population.

Surveillance data will provide accurate information about the incidence in the population and will enable us to monitor trends.

How should I report case(s) if I suspect this diagnosis?

Should SARS be suspected, telephone your local medical officer of health immediately.

Information to be provided to local medical officer of health would include the patient’s name, sex, and age, address, symptoms, travel history, and if the person has been in contact with a known probable or suspect case.

Surveillance Case definition:

Case definitions are subject to revision as further epidemiological/laboratory information becomes available.

Suspect Case:

A person presenting with:  Fever (over 38 degrees Celsius)

AND

One or more respiratory symptoms including cough, shortness of breath, difficulty breathing

AND

One or more of the following:

Close contact* within 10 days of onset of symptoms with a probable case

History of travel within 10 days to WHO reported “affected areas” in Asia

AND

No other known cause of current illness

*Close contact means having cared for, lived with or had face-to-face (within 1 metre) contact with, or having had direct contact with respiratory secretions and/or body fluids of a person with SARS.

Probable Case:

A person meeting the suspect case definition together with severe progressive respiratory illness suggestive of atypical pneumonia or acute respiratory distress syndrome with no known cause.

OR

A person with an unexplained acute respiratory illness resulting in death, with an autopsy examination demonstrating the pathology of acute respiratory distress syndrome with no known cause.

Additional Information:

In addition to fever and respiratory symptoms, SARS may be associated with headache, myalgia, loss of appetite, malaise, confusion, rash and diarrhea.

SARS may also be characterized by decreased oxygen saturation. Chest X-ray abnormalities may or may not be present.

Diagnostic Information:

In addition to clinically indicated laboratory testing conducted at the local level, the following specimens should be collected for all patients meeting the probable case definition and for all suspect cases with close contacts to probable cases:

Acute and convalescent blood for serology with at least 2 weeks between acute and convalescent samples.

·        Red tube (10mL minimum).

·        Lavender tube - (7mL minimum) for amplification tests.

·        Throat swab in viral transport media.

·        Nasopharyngeal swab or aspirate in viral transport medium (2mL).

·        Stool for virology - fresh or in viral transport media (if diarrhea is present). Not in Preservative.

AND WHERE POSSIBLE

Bronchial alveolar lavage or tracheal aspirate in a sterile container.

VIII. If a probable or suspect case had additional symptoms of meningitis- CSF for virology - fresh specimen in CSF tube.

IX. All tissues from biopsy or autopsy, fresh and fixed: i.e. lung, liver, spleen, brain etc.

Laboratories should follow normal testing procedures and refer specimens where necessary to the appropriate reference laboratories.

Early in the course of disease, the absolute lymphocyte count is often low. Overall WBC counts have generally been normal or low. At the peak of the respiratory illness, up to half the patients have leukopenia and thrombocytopenia or low-normal platelet counts (50,000 - 150,000 / µl). Early in the respiratory phase, elevated creatine phosphokinase levels (up to 3000 IU / L) and hepatic transaminases (2- to 6-times the upper limits of normal) have been noted. Renal function has remained normal in the majority of patients.

Chest radiographs may be normal during the febrile prodrome and throughout the course of illness. However, in a substantial proportion of patients, the respiratory phase is characterized by early focal interstitial infiltrates progressing to more generalized, patchy, interstitial infiltrates. Some chest radiographs from patients in the late stages of SARS have also shown areas of consolidation.

Note: Evidence of human metapneumovirus (hMPV) has been found in specimens from six of the eight cases that are currently being studied in Canada.