Severe Acute Respiratory Syndrome (SARS)

Overview

What is SARS?

Severe acute respiratory syndrome (SARS) is a respiratory illness that first infected people in parts of Asia, North America, and Europe in late 2002 and early 2003. SARS is caused by a type of coronavirus, a family of viruses that often cause mild to moderate upper respiratory illness, such as the common cold. This virus is known as SARS-CoV.

Experts believe SARS may have first developed in animals because the virus has been found in civets—a catlike wild animal that is eaten as a delicacy in China—and other animals.¹ In the first outbreak, 8,096 people became sick with SARS and 774 died.²

How is SARS spread?

Like most respiratory illnesses, SARS is spread mainly through contact with infected saliva or droplets from coughing. You cannot get SARS from brief, casual exposure to an infected person, such as passing someone on the street. You need to be near someone [less than 3 ft (1 m)] or have close contact to become infected. Close contact includes living with or caring for a person who has SARS or breathing in air that an infected person exhaled. Outbreaks of SARS do not appear to be seasonal.

An infection may develop after:

• Sharing food or drink with an infected person.
• Hugging or kissing a person with SARS.
• Talking to an infected person who is within 3 ft (1 m) of you.
• Getting the tiny droplets on your hands by touching contaminated surfaces or objects and then touching your eyes, nose, or mouth.

It is possible SARS can be transmitted in other ways, such as by touching objects that are contaminated with feces from an infected person. This could happen if people do not wash their hands after using the bathroom.

The disease does not appear to spread from a mother to her baby at birth.¹

What are the symptoms?

The main symptoms are a fever higher than 100.4°F (38°C), a dry cough, shortness of breath, or difficulty breathing. A person with SARS also may experience a headache, muscle aches, a sore throat, fatigue, and diarrhea. Older people may feel generally unwell (malaise) and lose their appetite but not have a fever.¹ For some people the symptoms get worse quickly, making hospitalization necessary.

The incubation period—the time from when a person is first exposed to SARS until symptoms appear—is usually 3 to 7 days but may be as long as 10 days. Experts believe a person can spread the illness to others only while he or she has symptoms. As a precaution, however, the U.S. Centers for Disease Control and Prevention (CDC) recommends that people who have SARS stay home, except for doctor visits, until 10 days after their symptoms have gone away.

How is SARS diagnosed?

Your doctor may suspect SARS if you have a fever higher than 100.4°F (38°C)and you have either traveled to a SARS-affected area or been around a person who has SARS within the past 10 days.

Your doctor may order several tests to determine the cause of your symptoms. A chest X-ray may be done if you are short of breath or coughing. A blood sample, sputum sample, or nasal swab may be done to detect bacteria or viruses. Your doctor may suspect that you have SARS if tests rule out any other cause for your symptoms, especially if you had contact with someone who has SARS or you traveled to an area experiencing a SARS outbreak. In this case, blood tests may be done to detect substances in your blood (antibodies) that form to fight the SARS virus.

You will need at least two tests for antibodies done on separate days to confirm an infection. You also may have tests to detect the genetic material (RNA) of the SARS virus. However, RNA testing is not available everywhere.

How is it treated?

Severe cases of SARS often require hospitalization, especially if breathing problems develop. You will be placed in isolation to prevent passing the disease to others. Various medications—including corticosteroids and the antiviral medication ribavirin—have been used to treat SARS, but no medication is known to cure the illness. Doctors continue to search for an effective treatment. One early study showed that the antiviral medication interferon alfacon-1, taken along with corticosteroids, may help in the treatment of SARS by increasing the amount of oxygen in the blood.³

About one-third (33%) of the people with SARS become ill and then recover.⁴ The illness gets worse in two-thirds (67%) of the people and is likely to lead to hospitalization.

The risk of dying from SARS depends on a person's age and health. The greatest risk is to people older than 65 and those with chronic illnesses, such as diabetes and heart disease. About 9 in 10 people infected with SARS recover; about 1 in 10 dies.^{5, 6}

How can I avoid being infected with SARS?

The best way to prevent the spread of SARS is to avoid areas where there is an outbreak and avoid contact with people who may be infected. You can also reduce your risk of infection by washing your hands often with soap or alcohol hand cleaners. If an outbreak occurs, try to avoid large public gatherings. The CDC does not recommend wearing face masks in public to prevent infection, although this is a common practice in Asian countries such as Japan.

Researchers are currently testing a vaccine for SARS; however, it may be several years before a vaccine is available.

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Author:	Maria G. Essig, MS, ELS	Last Updated August 2, 2007
Medical Review:	Caroline S. Rhoads, MD - Internal Medicine W. David Colby, MSc, MD, FRCPC - Infectious Disease
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