| Severe Acute
Respiratory Syndrome (SARS) |
| On
this page: |
| |
| Other pages: |
|
THE
DISEASE
What is SARS?
Severe acute respiratory syndrome (SARS) is a viral respiratory illness
that was recognized as a global threat in March 2003, after first
appearing in Southern China in November 2002.
What are the symptoms and signs of SARS?
The illness usually begins with a high fever (measured temperature greater than
100.4°F [>38.0°C]). The fever is sometimes associated with chills
or other symptoms, including headache, general feeling of discomfort, and
body aches. Some people also experience mild respiratory symptoms at the
outset. Diarrhea is seen in approximately 10 percent to 20 percent of patients.
After 2 to 7 days, SARS patients may develop a dry, nonproductive cough that
might be accompanied by or progress to a condition in which the oxygen levels
in the blood are low (hypoxia). In 10 percent to 20 percent of cases, patients
require mechanical ventilation. Most patients develop pneumonia.
What is the cause of SARS?
SARS is caused by a previously unrecognized coronavirus, called
SARS-associated coronavirus (SARS-CoV). It is possible that other
infectious agents might have a role in some cases of SARS.
How is SARS spread?
The primary way that SARS appears to spread is by close
person-to-person contact. SARS-CoV is thought to be transmitted most
readily by respiratory droplets (droplet spread) produced when an
infected person coughs or sneezes. Droplet spread can happen when
droplets from the cough or sneeze of an infected person are propelled a
short distance (generally up to 3 feet) through the air and deposited
on the mucous membranes of the mouth, nose, or eyes of persons who are
nearby. The virus also can spread when a person touches a surface or
object contaminated with infectious droplets and then touches his or
her mouth, nose, or eye(s). In addition, it is possible that SARS-CoV
might be spread more broadly through the air (airborne spread) or by
other ways that are not now known.
What does "close contact" mean?
Close contact is defined as having cared for or lived with a person
known to have SARS or having a high likelihood of direct contact with
respiratory secretions and/or body fluids of a patient known to have
SARS. Examples include kissing or embracing, sharing eating or drinking
utensils, close conversation (within 3 feet), physical examination, and
any other direct physical contact between people. Close contact does
not include activities such as walking by a person or briefly sitting
across a waiting room or office.
If I were exposed to SARS-CoV, how long would it take for me to become sick?
The time between exposure to SARS-CoV and the onset of symptoms is
called the "incubation period." The incubation period for SARS is
typically 2 to 7 days, although in some cases it may be as long as 10
days. In a very small proportion of cases, incubation periods of up to
14 days have been reported.
How long is a person with SARS infectious to others?
Available information suggests that persons with SARS are most likely
to be contagious only when they have symptoms, such as fever or cough.
Patients are most contagious during the second week of illness.
However, as a precaution against spreading the disease, CDC recommends
that persons with SARS limit their interactions outside the home (for
example, by not going to work or to school) until 10 days after their
fever has gone away and their respiratory (breathing) symptoms have
gotten better.
Is a person with SARS contagious before symptoms appear?
To
date, no cases of SARS have been reported among persons who were
exposed to a SARS patient before the onset of the patient's symptoms.
What medical treatment is recommended for patients with SARS?
CDC recommends that patients with SARS receive the same treatment that
would be used for a patient with any serious community-acquired
atypical pneumonia. SARS-CoV is being tested against various antiviral
drugs to see if an effective treatment can be found.
If there is another outbreak of SARS, how can I protect myself?
If transmission of SARS-CoV recurs, there are some common-sense
precautions that you can take that apply to many infectious diseases.
The most important is frequent hand washing with soap and water or use
of an alcohol-based hand rub. You should also avoid touching your eyes,
nose, and mouth with unclean hands and encourage people around you to
cover their nose and mouth with a tissue when coughing or sneezing.
GLOBAL
SARS OUTBREAK, 2003
How many people contracted SARS worldwide during the 2003 outbreak? How many people died of SARS worldwide?
During November 2002 through July 2003, a total of 8,098 people
worldwide became sick with severe acute respiratory syndrome that was
accompanied by either pneumonia or respiratory distress syndrome
(probable cases), according to the World Health Organization (WHO). Of
these, 774 died. By late July 2003, no new cases were being reported,
and WHO declared the global outbreak to be over. For more information
on the global SARS outbreak of 2003, visit WHO's SARS website.
How
many people contracted SARS in the United States during the 2003
outbreak? How many people died of SARS in the United States?
In the United States, only eight persons were laboratory-confirmed as
SARS cases. There were no SARS-related deaths in the United States. All
of the eight persons with laboratory-confirmed SARS had traveled to
areas where SARS-CoV transmission was occurring.
CURRENT
SARS SITUATION, 2004
Updated
Apr 26, 2004
What is the current SARS situation in the world?
In April 2004, the Chinese
Ministry of Health reported several new cases of possible SARS in Beijing
and in Anhui Province, which is located in east-central China. As of April
26, the Ministry of Health had reported eight possible SARS cases: six
in Bejing and two in Anhui Province. One of the patients in Anhui Province
died. Nearly 1000 contacts of these patients with possible SARS are under
medical observation, including 640 in Beijing and 353 in Anhui.
In addition, health
authorities have reported that two doctors who treated one of one of the
patients during her hospitalization in Anhui have developed fever. A person
in close contact with one of the doctors has also developed fever.
To date, all diagnosed
cases and cases under investigation have been linked to chains of transmission
involving close personal contact with an identified case. There is no
evidence of wider transmission in the community. For additional information
on the SARS situation in China, see www.who.int/csr/don/2004_04_26/en.
CDC is monitoring this
evolving situation in China and will provide additional information on
this website as it becomes available.
At this time,
CDC is not advising changes in the current U.S. SARS control
measures other than the recommendations stated in the HAN
Information Update for April 23. This update contains additional details
about the reported SARS cases. For updates on the current situation
regarding SARS, refer to other pages on CDC's
SARS website. Travel information is provided on CDC's
Travelers' Health website.
SARS-ASSOCIATED CORONAVIRUS
What are coronaviruses?
Coronaviruses are a group of viruses that have a halo or crown-like
(corona) appearance when viewed under a microscope. These viruses are a
common cause of mild to moderate upper-respiratory illness in humans
and are associated with respiratory, gastrointestinal, liver and
neurologic disease in animals.
If
coronaviruses usually cause mild illness in humans, how could this new
coronavirus be responsible for a potentially life-threatening disease
such as SARS?
There is not enough information about the
new virus to determine the full range of illness that it might cause.
Coronaviruses have occasionally been linked to pneumonia in humans,
especially people with weakened immune systems. The viruses also can
cause severe disease in animals, including cats, dogs, pigs, mice, and
birds.
How long can SARS-CoV survive in the environment?
Preliminary studies in some research laboratories suggest that the
virus may survive in the environment for several days. The length of
time that the virus survives likely depends on a number of factors.
These factors could include the type of material or body fluid
containing the virus and various environmental conditions such as
temperature or humidity. Researchers at CDC and other institutions are
designing standardized experiments to measure how long SARS-CoV can
survive in situations that simulate natural environmental conditions.
LABORATORY TESTING
Is there a laboratory test for SARS?
Yes, several laboratory tests can be used to detect SARS-CoV. A reverse
transcription polymerase chain reaction (RT-PCR) test can detect
SARS-CoV in clinical specimens such as blood, stool, and nasal
secretions. Serologic testing also can be performed to detect SARS-CoV
antibodies produced after infection. Finally, viral culture has been
used to detect SARS-CoV.
What is a PCR test?
PCR (or polymerase chain reaction) is a laboratory method for detecting
the genetic material of an infectious disease agent in specimens from
patients. This type of testing has become an essential tool for
detecting infectious disease agents.
What does serologic testing involve?
A serologic test is a laboratory method for detecting the presence
and/or level of antibodies to an infectious agent in serum from a
person. Antibodies are substances made by the body's immune system to
fight a specific infection.
What does viral culture and isolation involve?
For a viral culture, a small sample of tissue or fluid that may be infected is
placed in a container along with cells in which the virus can grow. If the
virus grows in the culture, it will cause changes in the cells that can be
seen under a microscope.
|
