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Notifying cases of infectious diseases within Victoria - What to notify

Infectious disease regulations
Includes School exclusion table

Severe Acute Respiratory Syndrome (SARS)

Other infectious diseases and conditions

Severe acute respiratory syndrome (SARS)

Victorian statutory requirement

SARS – CoV infection (Group A disease) must be notified immediately by telephone or fax followed by written notification within five days.

Infectious agent

SARS-associated coronavirus (SARS-CoV).

Identification

Clinical features
Severe Acute Respiratory Syndrome (SARS) is a recently recognised lower respiratory tract infection. In the first week of illness the patient develops influenza-like symptoms, which include fever, malaise, myalgia, headache, and rigors. No individual symptom or cluster of symptoms has proven specific, however a history of fever is the one most frequently reported.

The patient progresses to develop a cough (initially dry), dyspnoea and often diarrhoea (large volume and watery) usually in the second week of illness, although these features may occur earlier.

Severe cases progress to a rapidly increasing respiratory distress and oxygen desaturation of which approximately 20% require intensive care.

Upper respiratory symptoms such as rhinorrhea and sore throat may occur but are uncommon.

Method of diagnosis and case definition
Any specific testing for SARS should only be performed after consultation with the Communicable Diseases Section of the Department of Human Services (DHS), (see Guidance for recognition, investigation and infection control of SARS and avian influenza, www.health.gov.au/

At that time the status of any outbreak can be ascertained, the exposure and epidemiological links clarified, the case may be notified, appropriate infection control processes confirmed, and suitable patient transfer arranged.

The testing algorithm for SARS is heavily dependent upon the prevalence of the disease worldwide and locally, and this can be found on Department of Health and Ageing web site www.health.gov.au/

The microbiological investigation of a possible SARS infected patient will include the concurrent testing for other more common and likely respiratory pathogens through normal means (sputum, blood, nasal swabs, urine) as well as specific tests aimed to detect SARS-CoV.

The samples to be collected for SARS CoV specifically include:

a left and right nasal swab and a posterior pharyngeal wall swab all placed into the same viral transport medium. These can have PCR testing for many different respiratory viruses (respiratory multiplex) as well as for SARS-CoV if that is considered appropriate. An alternative to this is a nasopharyngeal aspirate
stool samples if diarrhoea is present
serum for antibody titres and, where appropriate, convalescent serum for parallel testing.

Testing is only performed at the Victorian Infectious Diseases Reference Laboratory (VIDRL) and all tests should be clearly labelled ‘For urgent SARS testing at VIDRL’.

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
  www.health.gov.au/
- residing in an area with recent local transmission of SARS

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: 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)

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 possibility of exposure
Visited a SARS affected area, but was in transit for less than 8 hours (in total, if multiple stopovers) and remained within the airport.
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.

Laboratory confirmed SARS
A person with symptoms and signs that are clinically suggestive of SARS

AND

With positive laboratory findings for SARS-CoV, based on one or more of the following diagnostic criteria:

a) PCR positive for SARS-CoV
PCR positive 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 (e.g. 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.

b) Seroconversion by ELISA or IFA

Negative antibody test on acute serum followed by positive antibody test on convalescent phase serum tested in parallel OR
Fourfold or greater rise in antibody titre between acute and convalescent phase sera tested in parallel.

c) Virus isolation

Isolation in cell culture of SARS-CoV from any specimen AND
PCR confirmation using a validated method.

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 re-evaluated 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 of 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’.

Maintaining vigilance and SARS alert clusters
If SARS does reemerge, it is unlikely but not impossible, that the first place it is recognised will be Australia. The most likely scenario is that this will occur in another country or countries (particularly Southern China, the source of the original outbreak), providing time for Australia to institute targeted surveillance and investigation of illness in travelers from defined outbreak areas, as was undertaken in the initial outbreak period.

Although both WHO and Australian health authorities regard Australia as a low likelihood country to first recognise a new SARS outbreak, a cautious approach is being taken. Maintaining vigilance for SARS (www.health.gov.au/) is a surveillance protocol that seeks to ensure that Australian health authorities will detect any new SARS outbreak by the detection of ‘alert’ clusters of cases. These are clusters of apparent hospital-acquired cases in staff, patients, and visitors to the same health-care facility, and that meet the new WHO post outbreak clinical case definition for SARS.

Definition of a SARS alert
a) Two or more health care workers in the same health care facility fulfilling the clinical case definition of SARS (see below) and with onset of illness in the same ten day period.

b) Apparent 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 facility fulfilling the clinical case definition of SARS (see below) and with onset of illness in the same 10-day period.

Clinical case definition of SARS alert cases (post-outbreak period)
The following clinical case definition has been developed for public health purposes.
A person with a history of:

a) Fever (≥ 38?C)

AND

b) One or more symptoms of lower respiratory tract illness (cough, difficulty breathing,
shortness of breath)

AND

c) Radiographic evidence of lung infiltrates consistent with pneumonia or acute respiratory distress syndrome (ARDS) OR autopsy findings consistent with the pathology of pneumonia or RDS without an identifiable cause.

AND

d) No alternative diagnosis can fully explain the illness.

If ‘alert’ clusters are detected from one institution then those cases should be urgently isolated and the situation immediately discussed with an infectious disease physician AND with the Communicable Disease Section, DHS. This is likely to lead to testing for SARS-coronavirus and the adoption of enhanced infection control measures.

Incubation period

The mean incubation period is five days with the range of 2–10 days although there are infrequent isolated reports of longer incubation periods.

Public health significance & occurrence

SARS came to the world’s attention in early 2003 when WHO declared a global public health alert in response to a severe respiratory illness due to an unidentified communicable pathogen.

The pathogen emerged out of Southern China creating a local outbreak of atypical pneumonia and subsequent infection of international travellers resulted in the importation of possible SARS cases to 29 other countries around the world. Hong Kong, Hanoi, Singapore and Toronto received such infected travellers early in the outbreak and further transmission within these cities resulted in local outbreaks, affecting many hundreds of people.

The overall case fatality rate was approximately 10% and was highest (>50%) in those over 60 years of age. A characteristic feature of the SARS outbreak was its unprecedented degree of nosocomial spread, which resulted in 21% of all cases involving health care workers. This has resulted in a requirement for heath care staff to adopt a new standard of infection control and personal protection.

WHO declared the outbreak interrupted on 5 July 2003 at which time there were more than 8400 cases and approximately 900 deaths. Mainland China reported over 5300 cases and 349 deaths. Australia had a single confirmed case of SARS who had visited NSW prior to the global alert and was detected in retrospect by authorities in her home country. She did not transmit the illness to any of her close contacts.

Five international flights were associated with the transmission of SARS however there has been no evidence of confirmed transmission on any flights after WHO recommended control measures, which included border exit screening.

Reservoir

There has been much interest in determining the source of this new virus, with particular focus on the animal species involved and animal husbandry methods seen in Southern China. Early investigations have pointed in the direction of certain animal species (palm civet, racoon dog) however these are not conclusive and more work in this area needs to be completed.

Mode of transmission

During the SARS outbreak, the predominant mode of transmission of the SARS CoV appeared to be by direct mucus membrane contact with respiratory droplets from either infected persons or fomites.

The evidence to date suggests that spread is predominantly through direct contact or exposure to larger virus-laden droplets that are thought to travel only one to two metres, than by lighter airborne particles. It has been postulated that these lighter and smaller aerosols may have been generated by procedures such as nebulisers or intubations, resulting in episodes where significant amplification of transmission was observed.
Infective stool may also pose a transmission risk but the risks associated with this are not yet clear.

New cases occurred primarily in persons with close contact to those very ill with SARS, which was seen in health care and household settings. Less frequently, transmission occurred to casual and social contacts after intense exposure to a case of SARS (in workplaces, airplanes or taxis).

Maximum excretion of the virus from the respiratory tract seems to occur near day 10 of illness and then declines. The efficiency of transmission appears to be greatest following exposure to severely ill patients or those experiencing rapid clinical deterioration, both of which usually occur during the second week of illness.

On reviewing cases of SARS it was found that when symptomatic cases were isolated within 5 days following onset of illness, few cases of secondary transmission occurred.

Period of communicability

SARS-CoV is not thought to be transmissible during the asymptomatic incubation period and there has been no evidence that the virus has been spread ten days after fever has resolved.

Susceptibility & resistance

The elderly are more prone to severe disease and pose a particular challenge in the recognition of SARS as they may present with an afebrile illness or with a concurrent bacterial sepsis or pneumonia.

In the setting of a SARS outbreak the diagnosis should be considered for almost any change in health status, even in the absence of typical clinical features of SARS-CoV disease, when such patients have epidemiologic risk factors for SARS-CoV disease (e.g. close contact with someone suspected to have SARS-CoV disease or exposure to a location [domestic or international] with documented or suspected recent transmission of SARS-CoV).

During the 2003 outbreaks, infants and children accounted for only a small percentage of patients and had much milder disease with better outcomes. There have been two reported cases of transmission from children to adults and no reports of transmission from children to other children. Three separate epidemiological investigations have found no evidence of SARS transmission in schools. Furthermore, no evidence of SARS has been found in infants of mothers who were infected during pregnancy. Further investigation is required to determine whether children may have asymptomatic or mild infections.

Control measures

Preventive measures
There are no vaccines available for SARS-CoV.

As a result of the global outbreak of SARS there has been resurgence in interest and prominence of respiratory hygiene and cough etiquette as an attempt to reduce transmission of all forms of respiratory pathogens, including SARS-CoV.

This includes encouraging all persons with signs and symptoms of a respiratory infection to:

cover the nose and mouth when coughing or sneezing
use tissues to contain respiratory secretions
dispose of tissues in the nearest waste receptacle after use
wash hands after contact with respiratory secretions and contaminated objects and materials.

Health care facilities should ensure the availability of materials for adhering to respiratory hygiene/cough etiquette in waiting areas for patients and visitors:

provide tissues and no-touch receptacles for used tissue disposal
provide conveniently located dispensers for alcohol-based hand rub
provide soap and disposable towels/hand driers for hand washing where sinks are available.

During periods of increased respiratory infection in the community, it may be possible for healthcare facilities to offer surgical masks to persons who are coughing and encourage coughing persons to sit at least three feet away from others in waiting areas.

Healthcare workers should practice droplet precautions, in addition to standard precautions, when examining a patient with symptoms of a respiratory infection.

Once there exists an index of suspicion of SARS then the appropriate infection control measures need to be activated and suitable PPE worn, (see www.icg.health.gov.au). These will dependent on the specific facility involved and the resources available at the time. They include:

use of standard precautions (ie hand hygiene) and contact and droplet precautions (ie use of long-sleeved gowns, gloves and protective eyewear for contact with patient or environment)
use of airborne precautions that include the use of a P2 (N95 equivalent) mask (respirator) for all persons entering the room and where available, a negative pressure respiratory isolation room (with en-suite)
restriction of patient movement (and fitting of a surgical mask if they must leave their room)
avoiding the use of nebulisers, chest physiotherapy, bronchoscopy, gastroscopy or any intervention that may disrupt the respiratory tract
placing surgical masks over nasal oxygen prongs.

It will become increasingly important for clinicians to elicit epidemiological information from their patients as part of normal history taking. Travel history, recent attendance to hospitals or exposure to others who are ill, may assist in the refinement of a patient’s differential diagnosis and associated risk.

The following points may become appropriate to consider in the primary care setting as a means of managing the issues of SARS:

signage at the reception desk may advise potential cases to report their concerns to the practice as early as possible
any case that could be reasonably regarded as possibly SARS should be discretely offered a mask and diverted out of the waiting room and into a single room (e.g. returned travellers from affected region with SARS like symptoms)
if seen in the practice the clinician should close the door, open a window, turn off the air-conditioning, put on a mask (N2 if possible), gown, gloves and eye protection
wash hands after consultation
do not self contaminate by touching ones own mucus membranes with contaminated hands
make an assessment and call the Communicable Diseases Section, DHS, for an update of the SARS situation and to develop a suitable management strategy
where possible any cases of concern should be seen at home with the appropriate PPE.

For further details see the Australian interim control guidelines, www.health.gov.au/

Control of case
Suspected cases will be managed on their clinical merits with home care regarded as a suitable option if the domestic situation, including its suitability in terms of infection control, is judged to be adequate. In such circumstances, cases will be advised to voluntarily restrict their movements.

Probable and confirmed cases will require hospitalisation and isolation in a suitable health facility, which will be determined by the Communicable Diseases Section DHS in consultation with the treating clinician. The receiving hospital will activate its SARS protocol to suitably manage such a patient.

All suspected, probable and confirmed cases will be excluded from school and work until clearance is obtained from DHS.

There are no specific treatment recommendations for SARS. The application of intensive supportive therapy and empirical antimicrobial therapy, to cover other infective agents, is the usual approach. Antiviral and pulse steroid therapy have been used in the past, in different countries with varying degree of success.

Discontinuation of SARS isolation precautions
SARS isolation precautions should be discontinued only after consultation with the local public health authorities and the evaluating clinician.

Control of contacts
Only people who have been close to an unwell person with SARS are at any significant risk of acquiring infection. For this reason only close contacts are sought to implement public health contact tracing measures and control disease spread. A close contact is a person who has lived, worked or had other dealings with a SARS case that have caused them to be within a meter of the case or who has had direct contact with respiratory secretions from a case while not wearing personal protective equipment.

Contact tracing will be undertaken for those close contacts of probable cases of SARS who were exposed after the patient became symptomatic (see details in the Recommendations for tracing & managing contacts of SARS cases www.health.gov.au/.

Contact tracing will not be undertaken for suspected cases of SARS while SARS has not been locally transmitted in Australia.

The aims of contact tracing is to find, provide information to and manage persons those who may have been exposed to the SARS CoV and who may be incubating or have early signs of the disease. Management of these contacts depends on who they were exposed to and the circumstances surrounding the exposure.

Well close contacts will be placed under either passive or active surveillance, whilst all unwell close contacts of probable cases will be placed under active surveillance and isolated in an appropriate setting.

It should be remembered that one of the most important available measures to prevent the spread of SARS CoV is the application of respiratory precautions and scrupulous hand washing. Contacts should be advised of such and also for the need to seek immediate medical attention if they develop the initial symptoms of SARS. Daily temperature monitoring for ten days after a break in exposure from the SARS case is advisable.

Close contacts of cases or returned travellers from regions of SARS outbreak as defined by DoHA will be allowed to attend school on the provision that they remain completely asymptomatic. Such persons should measure their temperatures daily to ensure that fever is not present during the ten days incubation period.

Cleaning and disinfection
Early studies of SARS-CoV show that if uninterrupted by cleaning or disinfectants it can survive on surfaces in the environment, such as on stainless steel benches, plastic, wood or cotton, for between 12 and 72 hours. However, the virus is not difficult to kill. It is important to clean surfaces with detergent and water and then to disinfect them.

emember that disinfectants need the appropriate time at the appropriate concentration to be effective.

The different methods available for disinfecting include:

Heat (56 degrees Celsius) is very effective, so dishes, linen and other washable items can be disinfected by washing in hot water and detergent.

Alcohol is effective. Tests show that 75% ethanol kills the virus at room temperature in less than 5 minutes. Slightly lower concentrations of alcohol would take a slightly longer time. Alcohol can be found in alcohol rubs (for hands), alcohol impregnated wipes and swabs such as used to disinfect skin, and methylated spirits.

Acetone is effective. 10% acetone will kill the virus in less than 5 minutes.

Phenol (2%) is effective and may be found in some hospital grade disinfectants.

Bleach has not yet been tested against the SARS coronavirus. However bleach is an effective disinfectant for many other viruses and is likely to be effective. Surfaces to be disinfected with bleach must first be cleaned with detergent and water. An appropriate dilution of 1 in 100 of most household bleach provides sodium hypochlorite at 500 ppm.

Additional sources of information

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