NAME: Severe acute respiratory syndrome (SARS) associated coronavirus.
SYNONYM OR CROSS REFERENCE: SARS-CoV Footnote 1, Footnote 2, SCV Footnote 3, SCoV Footnote 4, CoV Footnote 5, and was referred to as “atypical pneumonia syndrome” in China before SARS was identified Footnote 2.
CHARACTERISTICS: A member of the family Coronaviridae Footnote 2, Footnote 6, Footnote 7, genus Coronavirus Footnote 6. First isolated in 2003 Footnote 8, Footnote 9, the SARS-CoV is a novel coronavirus that is phylogenetically distinct and only distantly related to other human coronaviruses Footnote 6, Footnote 10. SARS-CoV is a spherical enveloped virion measuring 80 to 140 nm in diameter Footnote 1, Footnote 8, with a single-stranded, linear, non-segmented, positive-sense RNA genome Footnote 6, Footnote 10.
PATHOGENICITY/TOXICITY: Most common initial symptoms include a fever greater than 38°C (100.4°F) Footnote 1, Footnote 2, often accompanied by myalgia, malaise, chills, a non-productive cough, and rigor Footnote 8, Footnote 9, Footnote 11. After 2 to 7 days, this is followed by respiratory symptoms such as a dry cough, shortness of breath, difficulty breathing or hypoxia Footnote 1, Footnote 2. In some cases, the respiratory symptoms become increasingly severe, and patients require oxygen support and mechanical ventilation Footnote 11. 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 Footnote 1. Diarrhoea is the most common extra-pulmonary manifestation Footnote 12, followed by hepatic dysfunction, dizziness, abnormal urinalysis, petechiae, myositis, neuromuscular abnormalities, and epileptic fits Footnote 1. The case-fatality rate is 9.6% Footnote 2, Footnote 13; however, in patients over 65 years of age this rate exceeds 50% Footnote 11. While infections in children appear to be milder than those in adults Footnote 14, SARS in pregnant women carries a significant risk of mortality Footnote 15.
EPIDEMIOLOGY: SARS-CoV is a novel virus that caused the first major pandemic of the new millennium Footnote 7-Footnote 9. The earliest known cases were identified in mid-November 2002 in the Guangdong Province of South-East China Footnote 5, Footnote 16. The index case was reported in Foshan, a city 24 km from Guangzhou Footnote 1, Footnote 5. Retrospective analysis revealed severe cases of the disease in 5 cities around Guangzhou over a period of 2 months, with many of the cases having had epidemiological links to the live-animal market trade Footnote 5. Subsequent to its introduction to Hong Kong in mid-February 2003, the virus spread to Vietnam, Singapore, Canada, the Philippines, the United Kingdom, the United States, and then back again to China Footnote 1. By the end of July 2003, SARS had spread to affect a reported 8,098 people in over 30 countries, across 5 continents, killing 774 people Footnote 2, Footnote 13, Footnote 17. Over half of these infections can be traced back to 1 index patient who arrived in Hong Kong on February 21, 2003, and 21% of all cases were healthcare workers. Although the World Health Organization declared the end of the SARS epidemic in early July 2003, sporadic outbreaks of SARS occurred in late 2003 and early 2004, due to laboratory incidents Footnote 18-Footnote 20, and community-acquired SARS in the city of Guangzhou, China Footnote 21.
HOST RANGE: Natural hosts include humans, Himalayan palm civets (Paguma larvata), racoon dogs (Nyctereutes procyonoides), Chinese ferret badgers (Melogale moschata), cats, and pigs Footnote 3, Footnote 4, Footnote 22. Experimental hosts include non-human primates, ferrets, golden hamsters, guinea pigs, mice, and rats Footnote 22.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: Person-to-person contact (direct mucous membrane contact (eyes, nose and mouth) with infectious respiratory droplets and/or direct contact with infected body fluids) and/or through exposure to fomites Footnote 23-Footnote 25. Other possible modes of transmission include through blood transfusions, or by sharps injuries Footnote 24.
COMMUNICABILITY: Communicability is at its greatest from severely ill patients or those experiencing rapid clinical deterioration. Transmission usually occurs on or after the 5th day of illness, which coincides with peak viral load in nasopharyngeal secretions on around the 10th day of illness Footnote 11, Footnote 12.
RESERVOIR: Bats are thought to be the natural reservoir for SARS-CoV Footnote 26. Research is ongoing to identify the specific reservoir species. SARS-CoV-like viruses with a high degree of sequence homology with SARS-CoV were found in horseshoe bats (Rhinolophus spp.) Footnote 27-Footnote 29. On the other hand, the horseshoe bat angiotensin-converting enzyme 2 (ACE2) was found in one study to be unable to act as a receptor for human SARS-CoV, unlike its human equivalent Footnote 30. Rhinolophus sinicus (Chinese Rufous Horshoe Bat) and Myotis daubentoni (Daubenton’s Bat) were found to be susceptible to SARS-CoV infection in this same study.
ZOONOSIS: Yes, most likely via Himalayan palm civets Footnote 4.
DRUG SUSCEPTIBILITY: Unknown.
SUSCEPTIBILITY TO DISINFECTANTS: Inactivated by common disinfection measures such as a 5 minute contact of household bleach Footnote 25, ice-cold acetone, ice-cold acetone/methanol mixture (40:60), 70% ethanol (10 minutes), 100% ethanol (5 minutes) paraformaldehyde, and glutaraldehyde Footnote 31.
SURVIVAL OUTSIDE HOST: Can survive for 4 days in diarrhoeal stool samples with an alkaline pH Footnote 25, more than 7 days in respiratory secretions at room temperature, for at least 4 days in undiluted urine and human serum at room temperature Footnote 32, up to 9 days in suspension, 60 hours in soil/water, more than a day on hard surfaces such as glass and metal Footnote 24, and 6 days in dried state Footnote 31. The virus does not survive well after drying on paper, but lasts longer on disposable, compared to cotton gowns Footnote 25.
SURVEILLANCE: None of the symptoms of SARS can be used to differentiate SARS from other causes of pneumonia; therefore, laboratory confirmation is the only form of diagnosis Footnote 1, Footnote 33. A positive viral culture from respiratory, faecal, urine, or tissue specimen or a fourfold rise in neutralising antibody titre taken upon admission and 28 days afterward is the most definitive evidence of SARS infection. Rapid detection of nucleic acid by RT-PCR Footnote 18, Footnote 34, or antigen by ELISA can be used as alternatives. Immunofluorescence Footnote 21, microneutralisation, electron microscopy Footnote 7, and chest radiography Footnote 14, Footnote 21 can also be used to diagnose SARS-CoV.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Clinical management of SARS relies largely upon supportive care Footnote 1. Ribavirin, corticosteroids, lopinavir, ritonavir, type 1 interferon, intravenous immunoglobulin, and SARS convalescent plasma, have all been used by physicians to treat SARS, but it is not possible to determine whether the treatments actually benefited patients during the SARS outbreak Footnote 35.
IMMUNIZATION: None Footnote 2.
LABORATORY-ACQUIRED INFECTIONS: Four incidences have been reported to date. The first case occurred in Singapore in September 2003 when a 27 year old graduate student contracted SARS while working with West Nile virus in a culture laboratory where SARS-CoV was being maintained Footnote 18. The second case occurred in December 2003 in Taiwan when a 44 year old researcher contracted the disease while testing herbal remedies against SARS-CoV Footnote 19. The third and forth cases occurred in China in late-March to mid-April 2004 when 2 CDC workers developed SARS after improperly inactivating a batch of SARS virus in the laboratory Footnote 20. Each case was contributed to poor understanding or lack of safety procedures while working with SARS-CoV.
SPECIAL HAZARD: None.
RISK GROUP CLASSIFICATION: Risk Group 3 Footnote 36.
CONTAINMENT REQUIREMENTS: Containment Level 3 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Personnel entering the laboratory should remove street clothing and jewellery, and change into dedicated laboratory clothing and shoes, or don full coverage protective clothing (i.e., completely covering all street clothing). Additional protection may be worn over laboratory clothing when infectious materials are directly handled, such as solid-front gowns with tight fitting wrists, gloves, and respiratory protection. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 37.
OTHER PRECAUTIONS: All activities with infectious material should be conducted in a biological safety cabinet (BSC) or other appropriate primary containment device in combination with personal protective equipment. Centrifugation of infected materials must be carried out in closed containers placed in sealed safety cups, or in rotors that are loaded or unloaded in a biological safety cabinet. The use of needles, syringes, and other sharp objects should be strictly limited. Open wounds, cuts, scratches, and grazes should be covered with waterproof dressings. Additional precautions should be considered with work involving animals or large scale activities Footnote 37.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up.
DISPOSAL: Decontaminate all materials for disposal by steam sterilisation, chemical disinfection, and/or incineration.
STORAGE: In sealed containers that are appropriately labelled and locked in a Containment Level 3 facility.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: September 2011
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada.
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2011