The severe acute respiratory syndrome (SARS) is a zoonotic illness caused by severe acute respiratory syndrome-related coronavirus (SARS-CoV), a coronavirus. The disease was first seen in the city of Foshan in Guangdong Province in China in 2002 and was traced back to the Himalayan (masked) palm civet, racoon dogs and the Chinese ferret-badger. All of these animals are sold in the live wild animal markets in China 1.
From 2002-2003 there were over 8,000 confirmed cases of SARS-CoV (21% of which were in health care workers), leading to 813 deaths 1. Outside of Asia, Canada was the most affected nation, with the majority of cases secondary to exposure within a healthcare facility. The severe acute respiratory syndrome crisis in Canada lead to a major revision of infection control practice, surge capacity planning and the formation of the Canadian public health agency 4.
At the time of writing this article (early 2020), there are no active reported cases of SARS-CoV infection worldwide.
Patients with SARS-CoV present with flu-like symptoms that will either show clinical improvement after the first week (30% of patients) or require intensive care treatment (20-30% of patients). A history of SARS-CoV contact is often found. Initial symptoms include 1-3:
- acute respiratory distress syndrome (ARDS)
- acute cardiac injury
- acute renal failure
The SARS-related coronavirus is a member of the Betacoronavirus genus, one of the genera of the Coronaviridae family of viruses. Coronaviruses are enveloped single-stranded RNA viruses, that are found in humans, many other mammals and birds. These viruses are responsible for pulmonary, hepatic, CNS and intestinal disease.
Hitherto, six coronaviruses have been known to be responsible for human diseases, two are zoonoses, COVID-19 and Middle East respiratory syndrome coronavirus (MERS-CoV), both of which may sometimes be fatal. The remaining four viruses are ubiquitous in human societies worldwide and cause mild coryzal illnesses.
In up to 21% of patients 1, the initial chest radiograph may be normal. It is important to note that the findings are quite non-specific and clinical context is of the utmost importance 3:
- focal opacity (most common)
- multifocal opacity often contrasted to the middle and lower zones
- ground-glass opacities (unilateral or bilateral)
Treatment and prognosis
No specific treatment exists for the severe acute respiratory syndrome. Patients are given broad-spectrum antibiotics as well as antivirals, steroids and supportive therapy 3. Vaccines for MERS-CoV, and by extension, other coronaviruses, are under development 5.
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- 2. Gu J, Korteweg C. Pathology and pathogenesis of severe acute respiratory syndrome. (2007) The American journal of pathology. 170 (4): 1136-47. doi:10.2353/ajpath.2007.061088 - Pubmed
- 3. Narinder S. Paul, Heidi Roberts, Jagdish Butany, TaeBong Chung, Wayne Gold, Sangeeta Mehta, Eli Konen, Anuradha Rao, Yves Provost, Harry H. Hong, Leon Zelovitsky, Gordon L. Weisbrod. Radiologic Pattern of Disease in Patients with Severe Acute Respiratory Syndrome: The Toronto Experience1. (2004) RadioGraphics. 24 (2): 553-63. doi:10.1148/rg.242035193 - Pubmed
- 4. Johnston LB, Conly JM. Severe acute respiratory syndrome: What have we learned two years later?. (2004) The Canadian journal of infectious diseases & medical microbiology = Journal canadien des maladies infectieuses et de la microbiologie medicale. 15 (6): 309-12. doi:10.1155/2004/964258 - Pubmed
- 5. Ng LFP, Hiscox JA. Coronaviruses in animals and humans. (2020) BMJ (Clinical research ed.). 368: m634. doi:10.1136/bmj.m634 - Pubmed