What is SARS?

Severe acute respiratory syndrome, commonly known as SARS, is an infectious viral disease. The virus is spread mainly through sneezes and coughs (airborne or droplet transmission) and infects the respiratory tract.

The SARS virus first emerged in late 2002 in Guangdong, China, causing a large-scale outbreak that resulted in hundreds of deaths. [1] [2]  The outbreak was finally contained after a successful international effort (see Epidemiology, below).

Respiratory tract

The sections of the body used for breathing, including the mouth, nose, throat and lungs.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

2. Groneberg, D.A., Hilgenfeld, R. & Zabel, P. (2005) Molecular mechanisms of severe acute respiratory syndrome (SARS). Respiratory Research 6:8-24.

Epidemiology

The SARS virus most likely originated in bats and passed to humans through civet cats (small mammals native to tropical Asia and Africa). It is thought the virus moved from civet cats to humans in 'exotic meat' markets, where live wild animals are sold.

The SARS virus first emerged in late 2002 in Guangdong, China. It spread rapidly across the world, reaching 28 countries, causing 8,098 people to fall ill (20% of them were healthcare workers). [1] [3]  Of these people, 774 died. People over 65 years old were severely affected, with a 50% mortality rate in that age group. [3] [4]

A global health alert was announced in early 2003 and a large-scale international effort to contain the virus followed. Because regular infection control methods failed to prevent the spread of the virus, people with SARS had to be quarantined for the duration of the disease. Travel restrictions were also put into place.

The epidemic finally ended in July 2003. There have been no known cases of SARS since early 2004. The SARS epidemic had demonstrated that the world in the 21st century is truly a 'global village'. International travel is common and can lead to infectious disease spreading quickly across the world. This realisation led to the adoption of the International Health Regulations (IHR) in 2005, a legally-binding agreement that coordinates the global response to infectious epidemics.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Causes

The cause of SARS is the SARS coronavirus (SARS-CoV). This virus belongs to the coronavirus family, which also includes the virus that causes Middle East respiratory syndrome (MERS). When the SARS virus enters the lungs, it can damage lung cells and cause inflammation.

When an infected person sneezes or coughs, the SARS virus spreads into the air via millions of tiny droplets, each containing many viruses. If a droplet enters your nose or mouth, you may then become infected. The droplets can also collect on surfaces and objects, so you can also catch the virus by touching an infected surface and then touching your nose or mouth area. The SARS virus can also pass from person to person via the faecal-oral route.

The SARS virus can be spread via coughs or sneezes. 

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Risk factors

The main risk factor for SARS is being in close contact with a person infected with SARS. People over 65 years of age and people with other lung illnesses have a high risk of death from the infection.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Signs and symptoms

Signs and symptoms of SARS resemble those of influenza and other viral illnesses, and include:

  • Fever;
  • Sore throat;
  • Dry cough;
  • Breathing difficulties;
  • Discomfort (malaise);
  • Headache;
  • Chills;
  • Dizziness;
  • Stiff muscles;
  • Diarrhoea;
  • Loss of appetite, and;
  • Runny nose.

Not everyone who is infected with the virus will fall ill. The virus's incubation period is usually between two and seven days.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Methods for diagnosis

SARS can not be diagnosed by its symptoms alone. Your doctor will need to take nasal swabs, a blood sample or a stool sample from you and send it to a specialised laboratory for testing. Since SARS is a highly infectious disease and a high-level public threat, SARS tests are often high priority. Your doctor may also wish to have a chest X-ray taken.

X-ray

A scan that uses ionising radiation beams to create an image of the body’s internal structures.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Types of treatment

There is no specific treatment for SARS. A person suspected of being infected will be quarantined to prevent further spread, and can receive supportive treatment if necessary, which may include:

  • Breathing support (a ventilator);
  • Antiviral medication;
  • Antibiotic medication for treating secondary bacterial infections (usually pneumonia), and;
  • Anti-inflammatory medication.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Prognosis

Most people recover completely from SARS after a few weeks.  

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link

Prevention

There are currently no specific vaccines or antiviral medications to protect against SARS. You can prevent SARS from spreading by practising good hygiene measures, such as:

  • Avoiding contact with others;
  • Covering your mouth and nose when sneezing;
  • Washing your hands thoroughly;
  • Cleaning your surroundings;
  • Being alert about the risk of infection. Consult your doctor if you have any concerns, and;
  • If you think you may have SARS, call ahead to your health facility to discuss infection control measures such as wearing a facemask to reduce potential spread and to allow the health facility to adequately prepare for your arrival.  

Vaccines

A preparation containing a microorganism (that causes a specific disease) in a dead or weakened state, or parts of it, for the purpose of inducing immunity in a person to that microorganism.

1. Graham, R.L., Donaldson, E.F. & Baric, R.S. (2013) A decade after SARS: strategies for controlling emerging coronaviruses. Nature Reviews Microbiology 11:836–848.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

3. Madigan, M.T., Martinko, J.M., Bender, K.S., Buckley, D.H. and Stahl, D.A. Brock Biology of Microorganisms (14th global edition). Boston, US: Benjamin Cummins.

4. Severe acute respiratory syndrome (SARS). Centers for Disease Control and Prevention. Accessed 6 March 2015, from

External link