Severe acute respiratory syndrome (SARS)

The severe acute respiratory syndrome, or SARS, is caused by a novel coronavirus, which became known as the SARS coronavirus (SARS-CoV).¹ It is a highly contagious and potentially fatal respiratory disease that is spread mainly through the respiratory secretions produced by infected persons.² Since the virus first emerged in China in November 2002,³ there has been one global outbreak.⁴ During that epidemic in early 2003, the virus infected 8,096 people worldwide and resulted in 774 deaths.⁵ Singapore, with 238 cases and 33 deaths, was one of the worst-hit areas outside mainland China.⁶

Global outbreak in 2003
The origin of SARS has been traced to a then 45-year-old man in Foshan City, Guangdong, China.⁷ He became ill with fever and displayed respiratory symptoms in November 2002, and spread the disease to four relatives. However, he was not identified as the first SARS patient until much later.⁸

In early February 2003, the Guangdong Health Bureau reported that 305 people had been infected and five had died in an outbreak of atypical pneumonia in the province.⁹ Later that month, a physician who had unknowingly contracted the disease while working in a hospital in Guangdong travelled to Hong Kong and infected several fellow hotel guests, thereby setting off the international spread of SARS.¹⁰

On 12 March 2003, the World Health Organization (WHO) issued a global alert on outbreaks of atypical pneumonia in Guangdong, Hong Kong and Hanoi, Vietnam.¹¹ Three days later, WHO issued an emergency travel advisory and gave the disease its official name, severe acute respiratory syndrome.¹² Over the next few months, SARS spread to more than 20 other countries around the world.¹³ On 5 July 2003, WHO finally declared that the global outbreak had been contained.¹⁴

Since then, isolated cases have been reported in Singapore, Taiwan and Guangdong.¹⁵ The two cases in Singapore (September 2003) and Taiwan (December 2003) involved laboratory workers who had been infected in the course of their work because of safety lapses,¹⁶ while the source of three of four unrelated cases in Guangdong (December 2003–January 2004) was attributed to exposure to animal or environmental sources. The source of exposure in the fourth case was not identified conclusively.¹⁷ A minor outbreak also occurred in Beijing, China, in early 2004, involving two researchers who worked at an institute where experiments using SARS-CoV had been carried out. They were infected in late March and mid-April and transmitted the virus to nine others before the outbreak was contained by mid-May.¹⁸

Cause
The cause of SARS is SARS-CoV, which is distinct from previously known animal and human coronaviruses.¹⁹ It is thought to be an animal virus that somehow adapted to cross the species barrier to humans.²⁰ In January 2004, the Guangdong government banned the sale and consumption of masked palm civet cats, badgers and raccoon dogs and ordered the culling of 10,000 civet cats after researchers identified these animals as possible sources of SARS-CoV.²¹ These animals had traditionally been consumed as delicacies in southern China.²²

Coronaviruses have rounded projections extending out from their surface, giving them a crown-like appearance when seen under a microscope, hence their name (corona is Latin for “crown”).²³ They can lead to severe diseases in animals, including respiratory, gastrointestinal, reproductive, neurological, liver, kidney and generalised systemic diseases.²⁴ Coronaviruses also cause respiratory illnesses in humans; however, before SARS-CoV surfaced, these were usually mild.²⁵

Symptoms
Symptoms first appear two to 10 days after exposure to the virus, though there have been reports of longer incubation periods in a small number of cases.²⁶ The illness usually begins with a high fever (a temperature above 38°C).²⁷ This may be accompanied by other symptoms such as malaise, cough, chills, headache and muscle ache.²⁸ Less common symptoms include diarrhoea and skin rashes.²⁹ Later, some patients may experience shortness of breath and develop pneumonia. Most patients will gradually recover, but at least 10 percent will need intensive care and ventilators to help them breathe.³⁰

Transmission
SARS is spread primarily through the respiratory secretions of infected persons.³¹ The most common way that transmission occurs is when an infected person coughs or sneezes, thereby propelling respiratory droplets through the air, and the droplets are inhaled by people nearby or deposited on their mouth, eyes or nose.³² During the 2003 global outbreak, most of those who caught the virus were healthcare workers, family members and hospital patients or visitors who came into close contact with infected persons.³³

As the virus can survive in the environment for several hours, transmission can also occur when people touch surfaces (objects or parts of the body) that are contaminated by infectious respiratory secretions and then touch their nose, mouth or eyes.³⁴ Oral-faecal transmission is considered another possibility, as the virus has been found in the stool of infected persons.³⁵ Airborne transmission is also believed to be possible under certain circumstances.³⁶

Although SARS is spread through close contact, there have been no reports of anyone contracting the disease from being exposed to an infected person who was not yet showing any symptoms. Based on available information, it is apparent that infected persons are most contagious during the second week of illness.³⁷ It is likely, though not confirmed, that persons with SARS are contagious only after the onset of symptoms.³⁸

A super-spreading event is a situation where a single person is directly responsible for infecting a large number of people. For example, in the 2003 outbreak in Singapore, most of the cases were traced to just five super-spreaders.³⁹

Prevention
Effective prevention requires the quick detection and isolation of infected persons and measures to minimise people’s risk of contact with infected droplets.⁴⁰ Measures include the following:

• Detection and isolation:⁴¹ Mandatory temperature screening and declaration of travel history at travel checkpoints, medical facilities, public buildings and workplaces, self-monitoring of temperature, contact tracing and proper quarantine in a medical facility or at home.⁴²

• Infection control at hospitals: Ensure that medical workers are properly attired (by donning face mask, gloves and gown, for example) when in contact with patients and visitors, and limit the number of visitors.⁴³

• Public hygiene: Proper cleaning of public areas and frequently touched surfaces, and stringent hygiene standards for service staff such as food handlers.⁴⁴

• Personal hygiene and social responsibility: Stay home if unwell and wear a mask when going to see a doctor, cover nose and mouth with a tissue or handkerchief when coughing or sneezing,⁴⁵ wash hands with soap frequently, and do not share food unless a serving spoon is used.⁴⁶

Research laboratories around the world are still in the midst of developing a safe and effective human vaccine against SARS.⁴⁷ Since there is no vaccine available yet,⁴⁸ breaking the chain of transmission through preventive measures is currently the best way to thwart the spread of the virus.⁴⁹

Treatment
There is no treatment or medication specifically targeted at SARS.⁵⁰ So far, treatment methods have included a broad-spectrum antiviral drug called ribavirin, antibiotics, steroids, assisted ventilation or breathing support, and even traditional Chinese medicine.⁵¹



Author
Valerie Chew

References
1. “Frequently Asked Questions About Sars,” Centers for Disease Control and Prevention, accessed 18 March 2016; B. S. Kamps and C. Hoffmann, eds., Sars Reference, 3rd ed, 30, Sars Reference, accessed 18 March 2016.   
2. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars.”
3. “Update 95 – SARS: Chronology of a Serial Killer,” World Health Organization, accessed 10 February 2020.
4. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars.”
5. “Summary of Probable SARS Cases With Onset of Illness From 1 November 2002 to 31 July 2003,” World Health Organisation, accessed 10 February 2020; Centers
6. World Health Organization, “Summary of Probable SARS Cases With Onset of Illness From 1 November 2002 to 31 July 2003”; Kamps and Hoffmann, Sars Reference, 71.
7. Rolf Hilgenfeld and Malik Peiris, “From SARS to MERS: 10 Years of Research on Highly Pathogenic Human Coronaviruses” Antiviral Research 100 (2013): 287; SARS: How a Global Epidemic Was Stopped (Geneva: World Health Organization, 2006), 3. (Call no. RSING 614.592 SAR)
8. SARS: How a Global Epidemic Was Stopped, 3.
9. World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer”; Kamps and Hoffmann, Sars Reference, 15.
10. Hilgenfeld and Peiris, “From SARS to MERS,” 287; Kamps and Hoffmann, Sars Reference, 15, 64.
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12. World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer”; Kamps and Hoffmann, Sars Reference, 16; SARS: How a Global Epidemic Was Stopped, 259–61.
13. Hilgenfeld and Peiris, “From SARS to MERS,” 288; Kamps and Hoffmann, Sars Reference, 16–25.
14. World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer”; Kamps and Hoffmann, Sars Reference, 25.
15. World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS): Updated Recommendations (Geneva: World Health Organization, October 2004); SARS: How a Global Epidemic Was Stopped, 46.
16. World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS); SARS: How a Global Epidemic Was Stopped, 46.
17. World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS); SARS: How a Global Epidemic Was Stopped, 46.
18. SARS: How a Global Epidemic Was Stopped, 47.
19. A. Ho, “Up Close With the Czar of Sars,” Straits Times, 13 April 2003, 27 (From NewspaperSG); World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer.”
20. World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS).
21. “Civet Cull Ordered as Sars Confirmed,” South China Morning Post, 6 January 2004 (From Factiva via NLB’s eResources website); World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS).
22. World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer”; World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS).
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24. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; Kamps and Hoffmann, Sars Reference, 32.
25. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; Kamps and Hoffmann, Sars Reference, 33.
26. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS).
27. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars.”
28. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; Goh Chin Lian, “What You Need To Know,” Straits Times, 25 April 2003, 2 (From NewspaperSG); World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS).
29. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; Kamps and Hoffmann, Sars Reference, 124.
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31. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; SARS: How a Global Epidemic Was Stopped, 188.
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34. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars.”
35. Kamps and Hoffmann, Sars Reference, 49.9.
36. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; Kamps and Hoffmann, Sars Reference, 50.
37. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; SARS: How a Global Epidemic Was Stopped, 188.
38. Centers for Disease Control and Prevention, “Frequently Asked Questions About Sars”; SARS: How a Global Epidemic Was Stopped, 188, 193.
39. Kamps and Hoffmann, Sars Reference, 52, 70.
40. World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer.”
41. World Health Organization, “Update 95 – SARS: Chronology of a Serial Killer”; Ping-chung Leung and Eng Eong Ooi, eds., SARS War: Combating the Disease (Singapore: World Scientific, 2003), 65. (Call no. RSING 616.24 SAR)
42. World Health Organization, WHO Guidelines for the Global Surveillance of Severe Acute Respiratory Syndrome (SARS); SARS: How a Global Epidemic Was Stopped, 105–06; Leung and Eng, SARS War: Combating the Disease, 66; Chua Mui Hoong, A Defining Moment: How Singapore Beat SARS (Singapore: Institute of Policy Studies, 2004), 123, 132–35. (Call no. RSING 614.592 CHU)
43. Kamps and Hoffmann, Sars Reference, 89–90; Leung and Eng, SARS War: Combating the Disease, 83.
44. Leung and Eng, SARS War: Combating the Disease, 89, 96–97.
45. Goh, “What You Need To Know”; Leung and Eng, SARS War: Combating the Disease, 80–81.
46. Kamps and Hoffmann, Sars Reference, 100; Leung and Eng, SARS War: Combating the Disease, 80–81.
47. Ho, “Up Close With the Czar of Sars.”
48. SARS: How a Global Epidemic Was Stopped, 230–32.
49. SARS: How a Global Epidemic Was Stopped, 243–44
50. Goh, “What You Need To Know.”
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The information in this article is valid as at February 2020 and correct as far as we are able to ascertain from our sources. It is not intended to be an exhaustive or complete history of the subject. Please contact the Library for further reading materials on the topic.