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Last updated:
06 September 2004
1. Reason for surveillance
- To rapidly identify and isolate cases
- To identify and counsel contacts and ensure that they are isolated rapidly should symptoms occur
- To describe the epidemiology of suspected SARS in NSW.
2. Case definition
In inter-outbreak periods
Alert cases
In the absence of an alternate diagnosis:
- Two or more health care workers in the same health care unit fulfilling the clinical case definition of SARS and with onset of illness in the same 10-day period, OR
- Hospital acquired illness in three or more persons (health care workers and/or other hospital staff and/or patients and/or visitors) in the same health care unit fulfilling the clinical case definition of SARS and with onset of illness in the same 10-day period.
During outbreak periods
Suspect case
A person presenting after 1 November 2002 with history of:
- High fever (>38 °C), AND
- Cough or breathing difficulty, AND
- One or more of the following exposures during the 10 days prior to onset of symptoms
- Close contact with a person who is a suspect or probable case of SARS
- History of travel, to an area with recent local transmission of SARS (http://health.gov.au/sars/guidelines/cases.html)
- Residing in an area with recent local transmission of SARS.
OR:A person with an unexplained acute respiratory illness resulting in death after 1 November 2002, but on whom no autopsy has been performed AND one or more of the following exposures during to 10 days prior to onset of symptoms:
- Close contact with a person who is a suspect or probable case of SARS
- History of travel to an area with recent local transmission of SARS
- Residing in an area with recent local transmission of SARS.
CLOSE CONTACT is defined as having cared for, lived with, or had direct contact with respiratory secretions or body fluids of a suspect or probable case of SARS.Probable case
- A suspect case with radiographic evidence of infiltrates consistent with pneumonia or respiratory distress syndrome (RDS) on chest X-ray (CXR), OR
- A suspect case with autopsy findings consistent with the pathology of RDS without an identifiable cause.
Exclusion criteria
A probable or suspect case should be excluded if:
- NO CONVINCING POSSIBLITY OF EXPOSURE, e.g., visited a SARS affected area, but was in transit for less than 8 hours (in total, if multiple stopovers) and remained within the airport, or
- AN ALTERNATIVE DIAGNOSIS IS MADE, e.g., a clinical diagnosis of probable bacterial pneumonia, which could be defined by X-ray findings of lobar consolidation and clinical response to antibiotics. A case initially classified as suspect or probable, for whom an alternative diagnosis can fully explain the illness, should be discarded after carefully considering the possibility of co-infection.
A suspect case should be excluded if they have had a mild self limiting illness however, persons are not to be downgraded should signs of clinical illness remain.Confirmed Case
A confirmed case requires laboratory definitive evidence and clinical evidence. Laboratory definitive evidence
- Detection of severe acute respiratory syndromecoronavirus (SARS-CoV) by nucleic acid testing using a validated method from at least two different clinical specimens (e.g., nasopharyngeal and stool), or the same clinical specimen collected on two or more occasions during the course of the illness (eg sequential nasopharyngeal aspirates), or two different assays or repeat PCR using a new RNA extract from the original clinical sample on each occasion of testing, OR
- Seroconversion or significant increase in antibody level or fourfold or greater rise in titre to SARS-CoV tested in parallel by enzyme-linked immunosorbent assay or immunofluorescent assay, OR
- Isolation of SARS-CoV AND detection of SARSCoV by nucleic acid testing using a validated method.
Clinical evidence
A person with a history of:
- Fever (38°C), AND
- One or more symptoms of lower respiratory tract illness (cough, difficulty breathing), AND
- Radiographic evidence of lung infiltrates consistent with the pathology of pneumonia or acute respiratory distress syndrome (ARDS) OR autopsy findings consistent with the pathology of pneumonia or ARDS.
Reclassification of cases
A suspect case who, after investigation, fulfils the probable case definition should be reclassified as "probable".A suspect case with a normal CXR should be treated, as deemed appropriate, and monitored for 7 days. Those cases in whom recovery is inadequate should be reevaluated by CXR. A suspect case who dies, on whom no autopsy is conducted, should remain classified as "suspect". However, if this case is identified as being part of a chain transmission of SARS, the case should be reclassified as "probable". If an autopsy is conducted and no pathological evidence of RDS is found, the case should be "discarded". Factors to be considered in case identification
The confirmed case definition is based on that provided by WHO for use in the inter-outbreak period. It should be recognised that the case definition provided by WHO may be modified in the event of a second global alert. The surveillance case definitions are based on available clinical, epidemiological and laboratory data. Clinicians are advised that patients should not have their case definition category downgraded while awaiting results of laboratory testing or on the basis of negative laboratory tests if clinical suspicion remains. A patient should always be managed as clinically appropriate, regardless of their case status.
3. Notification criteria and procedure
SARS is to be notified to the PHU by:
- Medical practitioners, hospitals and laboratories (ideal reporting by telephone within 1 hour of diagnosis).
Health care workers should call PHUs to help in the triage and management of possible SARS cases. Only confirmed cases should be entered onto NDD, however PHUs should report ALERT, SUSPECTED, PROBABLE and CONFIRMED cases to the Communicable Diseases Branch (CDB) using the SARS Reporting Form on the day of notification.
4. The disease
Infectious agent
The coronavirus, SARS-CoV. Mode of transmission
SARS is spread mainly through droplet transmission. Faecal transmission and contact with fomites may play a role. Airborne transmission may occur from severely ill patients. Timeline
The incubation period for SARS is typically 2-7 days, but can range between 1 and 10 days (longer incubation periods have been postulated). Cases are most infectious in the second week of illness but can shed virus in stool and respiratory secretions (and may be infectious) for more than 3 weeks. Clinical presentation
The illness usually begins with a fever, and is associated with systemic symptoms such as headache, myalgia, and malaise. After 2 to 7 days, a lower respiratory phase begins and patients may develop a non-productive cough that can progress to shortness of breath. Around 20% of hospitalised cases require mechanical ventilation. In many patients, the respiratory phase is characterised by early focal interstitial infiltrates on chest x-ray that progress to more generalised patchy interstitial infiltrates or areas of consolidation. About 15% of hospitalised cases die. Cases who are elderly, immunocompromised or with co-morbidities have an increased mortality rate.
5. Managing single notifications
Response time
On the same day as notification of a possible case, begin follow up investigation using the SARS Reporting Form and notify the CDB. Data entry
Within 1 working day of notification, enter confirmed cases on NDD and forward completed SARS investigation form to CDB. Response procedure
The response to a notification will normally be carried out in collaboration with the case's health carers. Regardless of who does the follow-up, PHU staff should ensure that action has been taken to:
- Confirm the onset date and symptoms of the illness
- Confirm results of relevant pathology tests, or recommend that tests be done
- Find out if the case or relevant care-giver has been told what the diagnosis is before beginning the interview
- Seek the doctor's permission to contact the case or relevant care-giver
- Review case and contact management
- Ensure appropriate infection control guidelines are followed in caring for the case
- Identify the likely source of infection.
In general, cases should be managed in hospital. If clinically indicated, cases may be managed at home only if it can be ensured that the case and contacts are counselled about risk and that infection control measures are in place. The PHU must ensure that case and contact management follows the guidelines on the NSW Health Infectious Diseases Web page. Case management
Investigation
Complete the attached SARS Reporting Form, including the travel history, clinical results and case details, and forward to the CDB within 1 working day of notification. Education
Provide SARS Fact Sheets to cases and their close contacts. Ensure that they are aware of the signs and symptoms of SARS, the requirements of isolation, contact details of the PHU and the infection control practices that can prevent the transmission of SARS. Isolation and restriction
Cases must be isolated. Health care workers and others who come into contact with the case must be protected according to the latest guidelines. Cases can be detained in isolation under the NSW Public Health Act and the Commonwealth Quarantine Act. Environmental evaluation
Where local transmission of SARS is thought possible, a thorough review of contributing environmental factors should be done. This should include a review of infection control procedures, and opportunities for exposure to respiratory or faecal contamination. Contact management
Identification of contacts
A close contact is a person who has cared for, lived with, or had direct contact with respiratory secretions or body fluids of a suspect or probable case of SARS. Treatment
None. Education
Contacts should be counselled about their risk and the symptoms of SARS and placed under surveillance (see attached Advice Sheet). Isolation and restriction
Contacts may be restricted from entering certain facilities for 10 days after last exposure. Unwell contacts must be rapidly isolated until SARS is excluded.
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