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, which can cause mild to moderate
upper respiratory illness, such as the common cold. This virus is known as
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
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. In general,
you need to 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. But under some conditions, SARS has
spread within an apartment building and to health care workers.
Outbreaks of SARS do not appear to be seasonal.
An infection may develop
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
The disease does not appear to spread from a mother to
her baby at birth.1
The main symptoms are a
fever, 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. An older person may feel generally unwell (malaise) and lose his or her
appetite but not have a fever.1 For some people the
symptoms get worse quickly, making a hospital stay 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,
though, 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.
If you think you may have SARS, be sure to call your doctor before you go in to get checked. The doctor will need to make sure you do not infect other people.
Your doctor may suspect
SARS if you have a fever and you either have traveled to
a SARS-affected area or have in the past 10
days been around a person who has SARS.
Your doctor may order several tests to
find out 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. RNA testing is not available
Severe cases of SARS often
require a hospital stay, especially if breathing problems develop. You will be
placed in isolation to prevent passing the disease to others. Various
corticosteroids and the antiviral medicine
ribavirin—have been used to treat SARS. But no medicine is known to cure the
illness. Doctors continue to search for an effective treatment. One early study
showed that the antiviral medicine interferon alfacon-1, taken along with
corticosteroids, may help in the treatment of SARS by increasing the amount of
oxygen in the blood.3
(33 out of 100) of the people with SARS become ill and then recover.4 The illness gets worse in two-thirds (67 out of 100) of the people and
is likely to lead to hospitalization.
About 9 out of 10 people
infected with SARS recover. That means about 1 out of 10 people
infected with SARS dies.5, 6 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.
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.
currently trying to develop vaccines to
prevent SARS infection.
But no vaccines are being tested in humans
The following health
organizations are tracking and studying
severe acute respiratory syndrome (SARS). Their websites contain the most up-to-date information, including advice for
The Centers for Disease Control and Prevention (CDC) is
an agency of the U.S. Department of Health and Human Services. The CDC works
with state and local health officials and the public to achieve better health
for all people. The CDC creates the expertise, information, and tools that
people and communities need to protect their health—by promoting health,
preventing disease, injury, and disability, and being prepared for new health
The National Institute of Allergy and Infectious
Diseases conducts research and provides consumer information on infectious and
The World Health Organization (WHO) is an agency of the
United Nations. It has about 200 member states. WHO promotes technical
cooperation among nations on health issues, carries out programs to control and
eliminate disease, and strives to improve the quality of human life.
The Web site has information on many health topics, including health and
disease related to travel.
Peiris JSM, et al. (2003). The severe acute
respiratory syndrome. New England Journal of Medicine,
World Health Organization (2003). Summary of Probable SARS Cases With Onset of Illness From 1 November 2002 to 31 July 2003. Available online:
Loutfy MR, et al. (2003). Interferon alfacon-1 plus
corticosteroids in severe acute respiratory syndrome: A preliminary study.
JAMA, 290(24): 3222–3228.
Hayden FG and Ison MG (2006). Respiratory viral
infections. In DC Dale, DD Federman, eds., ACP Medicine,
section 7, chap. 25. New York: WebMD.
World Health Organization (2004).
WHO guidelines for the global surveillance of severe acute respiratory syndrome (SARS). Updated recommendations, October 2004. Available online:
Eun-Hyung Lee F, Treanor JJ (2010). Viral infections. In R Mason et al., eds., Murray and Nadels Textbook of Respiratory Medicine, 5th ed., vol. 1, pp. 661–698. Philadelphia: Saunders Elsevier.
May 28, 2013
E. Gregory Thompson, MD - Internal Medicine
& W. David Colby IV, MSc, MD, FRCPC - Infectious Disease
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