Download Severe Acute Respiratory Syndrome (SARS)

Severe Acute Respiratory Syndrome (SARS)
From DrGreene.com
Definition:
Severe Acute Respiratory Syndrome (SARS) is a contagious respiratory infection that was first described on February 26,
2003. It was first identified as a new disease by WHO physician Dr. Carlo Urbani who diagnosed it in a 48-year-old
businessman who had traveled from the Guangdong province of China, through Hong Kong, to Hanoi, Vietnam. The
businessman died from the illness. Dr. Urbani subsequently died from SARS on March 29, 2003 at the age of 46. In the
meantime, SARS began to spread, and within 6 weeks of its discovery, it had infected thousands of people around the world,
including people in Asia, Australia, Europe, and North and South America. Schools had closed throughout Hong Kong and
Singapore. National economies were affected. The WHO had identified SARS as a global health threat, and issued an
unprecedented travel advisory. But it wasn't clear whether SARS would become a global pandemic, or would settle into a less
aggressive pattern.
SARS is a serious form of atypical pneumonia, resulting in acute respiratory distress and sometimes death. It is a dramatic
example of how quickly world travel can spread a disease. It is also an example of how quickly a networked health system can
respond to an emerging threat.
Alternative Names:
SARS
Causes And Risk:
SARS appears to be caused by a virus or viruses. The first reports from virologists
suggested the cause was a new virus in the paromyxovirus family (the same family as RSV, measles, and mumps).
Subsequent evidence pointed more strongly to a new member of the coronavirus family (the same family that can cause the
common cold). The discovery of these viral particles represents some of the fastest identification of a new organism in history.
SARS is clearly spread by droplet contact. When someone with SARS coughs or sneezes, infected droplets are sprayed into
the air. With other coronaviruses, the virus can live on hands, tissues, and other surfaces for up to 6 hours in these droplets
and up to 3 hours after the droplets have dried. (Also, with other coronaviruses, re-infection is common.) While droplet
transmission through close contact was responsible for most of the early cases of SARS, evidence began to mount that SARS
might also spread by hands and other objects the droplets had touched. Airborne transmission was a real possibility in some
cases. Live virus had even been found in the stool of people with SARS.
Preliminary estimates are that the incubation period is usually between 2 and 7 days, although there have been documented
cases where the onset of illness was considerably faster or slower. People with active symptoms of illness are clearly
contagious, but it is not known how long contagiousness may begin before symptoms appear or how long contagiousness
might linger after the symptoms have disappeared.
Prevention:
Minimizing contact with people with SARS minimizes the risk of the disease. This might include minimizing travel to locations
where there is an uncontrolled outbreak. Where possible, direct contact with people with SARS should be avoided until 10
days after the fever and other symptoms are gone.
The CDC has identified hand hygiene as the cornerstone of SARS prevention. This might include hand washing or cleaning
hands with an alcohol-based instant hand sanitizer.
People should be taught to cover the mouth and nose when sneezing or coughing. Respiratory secretions should be
considered to be infectious, which means no sharing of food, drink, or utensils. Commonly touched surfaces can be cleaned
with an EPA approved disinfectant.
In some situations, masks and goggles may be useful for preventing airborne or droplet spread. Gloves might be used in
handling potentially infectious secretions.
Symptoms:
The hallmark symptoms are fever greater than 100.4 F (38.0 C) and cough, difficulty breathing, or other respiratory symptoms.
Symptoms found in more than half of the first 138 patients included (in the order of how commonly they appeared):

fever

chills and shaking

muscle aches

cough

headache
Less common symptoms include (also in order):

dizziness

productive cough (sputum)

sore throat

runny nose

nausea and vomiting

diarrhea
Signs And Tests:
Listening to the chest with a stethoscope (auscultation) may reveal abnormal lung sounds. In most people with SARS,
progressive chest X-ray changes or chest CT changes demonstrate the presence of pneumonia.
Much attention was given early in the outbreak to developing a quick, sensitive test for SARS.
General tests used in the diagnosis of SARS might include:

a chest X-ray or chest CT

a CBC (people with SARS tend to have a low white blood cell count (leukopenia), a low lymphocyte count
(lymphopenia), and/or a low platelet count (thrombocytopenia).

clotting profiles (often prolonged clotting)

blood chemistries (LDH levels are often elevated. ALT and CPK are sometimes elevated. Sodium and potassium
are sometimes low).
Treatment:
People suspected of having SARS should be evaluated immediately by a physician. Antibiotics are sometimes given in an
attempt to treat bacterial causes of atypical pneumonia. Antiviral medications have also been used. High doses of steroids
have been employed to reduce lung inflammation. In some serious cases, serum from people who have already gotten well
from SARS (convalescent serum) has been given. Evidence of general benefit of these treatments has been inconclusive.
Other supportive care such as supplemental oxygen, chest physiotherapy, or mechanical ventilation is sometimes needed.
Prognosis:
The early death rate in SARS was about 4 percent of those diagnosed. This is expected to change over time, as the virus and
available medical care both change. Between 10 and 20 percent of those diagnosed with SARS have been sick enough to
require mechanical ventilation. More than that have been sick enough to require ICU care.
Complications:

respiratory failure

liver failure

heart failure

myelodysplastic syndromes
What Is SARS?
Provided by Centers for Disease Control and Prevention
What is SARS?
Severe acute respiratory syndrome (SARS) is a respiratory illness that has recently been reported in Asia, North America, and
Europe.
The symptoms and signs of SARS
The illness usually begins with a fever (measured temperature greater than 100.4 蚌 [>38.0 蚓]). 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. After 2 to 7 days, SARS patients may develop a dry, nonproductive
cough that might be accompanied by or progress to the point where insufficient oxygen is getting to the blood. In 10 percent to
20 percent of cases, patients will require mechanical ventilation. For more information, see the MMWR dispatch.
If I were exposed to SARS, how long would it take for me to become sick?
The incubation period for SARS is typically 2 to 7 days; however, isolated reports have suggested an incubation period as long
as 10 days. The illness usually begins with a fever (>100.4 蚌 [>38.0 蚓]) (see signs and symptoms, above).
What medical treatment is recommended for patients with SARS?
CDC currently recommends that patients with SARS receive the same treatment that would be used for any patient with
serious community-acquired atypical pneumonia of unknown cause.
Is the use of ribavirin (or other antiviral drugs) effective in the treatment of patients with SARS?
At present, the most efficacious treatment regimen, if any, is unknown. In several locations, therapy has included antivirals
such as oseltamivir or ribavirin. Steroids also have been given orally or intravenously to patients in combination with ribavirin
and other antimicrobials. In the absence of controlled clinical trials, however, the efficacy of these regimens remains unknown.
Early information from laboratory experiments suggests that ribavirin does not inhibit virus growth or cell-to-cell spread of one
isolate of the new coronavirus that was tested. Additional laboratory testing of ribavirin and other antiviral drugs is being done
to see if an effective treatment can be found.
SARS Symptom Chart
Allergic Rhinitis Asthma Cold Flu Pneumonia SARS
Body Aches and Pains
• ••
••
••
••
••
••
•
•
•
Chills/Rigors
Cough
•
•
•
•
Diarrhea
•
Dizziness
•
Fatigue/Malaise
• •••
•••
••
Fever
• •••
•••
••
Headache
• ••
••
••
•• •
Nasal Congestion
••
Nausea/Vomiting
•
Painful Breathing
•
Productive Cough
Shortness of Breath
•
••
Sneezing
•
••
Sore Throat
•
•• •
•
•
•
•
••
••
•
•
•
KEY
•••
••
•
Blank
=
Commonly present, high or severe
=
Commonly present
=
Can be present
=
Not usually present
The SARS Virus
Provided by Centers for Disease Control and Prevention
A new disease called SARS
The Centers for Disease Control and Prevention (CDC) is investigating a new disease
called severe acute respiratory syndrome (SARS) that has recently been reported in Asia,
North America, and Europe. As of April 13, about 190 cases of SARS had been reported in
the United States. This fact sheet provides basic information about the disease and what is
being done to combat its spread.
Symptoms of SARS
In general, SARS begins with a fever greater than 100.4 蚌 [>38.0 蚓]. Other symptoms
may include headache, an overall feeling of discomfort, and body aches. Some people also experience mild respiratory
symptoms. After 2 to 7 days, SARS patients may develop a dry cough and have trouble breathing.
How SARS spreads
The primary way that SARS appears to spread is by close person-to-person contact. Most cases of SARS have involved
people who cared for or lived with someone with SARS, or had direct contact with infectious material (for example, respiratory
secretions) from a person who has SARS. Potential ways in which SARS can be spread include touching the skin of other
people or objects that are contaminated with infectious droplets and then touching your eye(s), nose, or mouth. This can
happen when someone who is sick with SARS coughs or sneezes droplets onto themselves, other people, or nearby surfaces.
It also is possible that SARS can be spread more broadly through the air or by other ways that are currently not known.
Who is at risk for SARS
Cases of SARS continue to be reported mainly among people who have had direct close contact with an infected person, such
as those sharing a household with a SARS patient and health care workers who did not use infection control procedures while
taking care of a SARS patient. In the United States, there is no indication of community spread at this time. CDC continues to
monitor this situation very closely.
Possible cause of SARS
Scientists at CDC and other laboratories have detected a previously unrecognized coronavirus in patients with SARS. The
new coronavirus is the leading hypothesis for the cause of SARS, however, other viruses are still under investigation
as potential causes.
CDC Lab Sequences Genome of New Coronavirus
Provided by Centers for Disease Control and Prevention
The Centers for Disease Control and Prevention (CDC) announced that it has sequenced the genome for the coronavirus
believed to be responsible for the global epidemic of severe acute respiratory syndrome or SARS. The CDC sequence is
nearly identical to that determined by a Canadian laboratory late last week. The significant difference is that the
CDC-determined sequence has 15 additional nucleotides, which provides the important beginning of the sequence, CDC
scientists said.
The results came just 12 days after a team of 10 scientists, supported by numerous technicians, began working around the
clock to grow cells taken from a throat culture taken from one of the SARS patients in Vero cells (African green monkey kidney
cells) in order to reproduce the ribonucleic acid (RNA) of the disease-causing coronavirus. The new sequence has 29,727
nucleotides, which places it well within the typical RNA boundaries for coronaviruses. Members of this viral family tend to have
between 29,000 and 31,000 nucleotides.
Identifying the genetic sequence of a new virus is important to efforts to treat or prevent it, said Dr. Julie Gerberding, CDC
director. "Research laboratories can use this information to begin to target antiviral drugs, to form the basis for developing
vaccines, and to develop diagnostic tests that can lead to early detection."
In sequencing the genome, CDC scientists worked closely with coronavirus experts at academic institutions across the United
States. "This is an active, working community of scientific experts who have been contributing their knowledge and expertise
throughout this investigation," said William Bellini, Ph.D., SARS laboratory team coordinator.
The nearly identical findings in the US and Canada are important because they were derived from different individuals who
were infected in different countries. This suggests that the virus probably originated from a common source.
The CDC's analysis of the virus is far from finished, officials emphasized. Because coronaviruses have the ability to mutate
rapidly, scientists will compare the sequences from viruses isolated in cell culture to those obtained from diseased tissues
taken from SARS patients. "This is essentially a draft. Now we need to see if what we have identified in the laboratory matches
what's causing disease in patients," Bellini said.
But the groundbreaking work of isolating the genomic sequence speeds the task of comparison