Severe acute respiratory syndrome (SARS) is a serious form of pneumonia. It is caused by a virus that was first identified in 2003. Infection with the SARS virus causes acute respiratory distress (severe breathing difficulty) and sometimes death.
SARS is a dramatic example of how quickly world travel can spread a disease. It is also an example of how quickly a connected health system can respond to a new health threat.
World Health Organization (WHO) physician Dr. Carlo Urbani identified SARS as a new disease in 2003. He 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 and the doctor who first diagnosed SARS both died from the illness.
In the meantime, SARS was spreading. Quickly it infected thousands of people around the world, including people in Asia, Australia, Europe, Africa, and North and South America. Schools closed throughout Hong Kong and Singapore. National economies were affected.
The WHO identified SARS as a global health threat, and issued a travel advisory. WHO updates closely tracked the spread of SARS. It wasn't clear whether SARS would become a global pandemic.
The fast global public health response helped to stem the spread of the virus. By June 2003, the number of new cases was down enough that on June 7, the WHO stopped its daily reports. But even though the number of new cases dwindled and travel advisories began to be lifted, every new case had the potential to spark another outbreak.
SARS appears to be here to stay. It has changed the way that the world responds to infectious diseases during a time of widespread international travel. The 2003 outbreak had an estimated 8,000 cases and 750 deaths.
Causes, incidence, and risk factors
SARS is caused by a member of the coronavirus family of viruses (the same family that can cause the common cold). It is believed the 2003 epidemic started when the virus spread from small mammals in China.
When someone with SARS coughs or sneezes, infected droplets spray into the air. You can catch the SARS virus if you breathe in or touch these particles. The SARS virus may 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.
While the spread of droplets through close contact caused most of the early SARS cases, SARS might also spread by hands and other objects the droplets has touched. Airborne transmission is a real possibility in some cases. Live virus has even been found in the stool of people with SARS, where it has been shown to live for up to 4 days. The virus may be able to live for months or years when the temperature is below freezing.
With other coronaviruses, becoming infected and then getting sick again (re-infection) is common. This may also be the case with SARS.
Symptoms usually occur about 2 to 10 days after coming in contact with the virus. There have been some cases where the illness started sooner or later after first contact. People with active symptoms of illness are contagious, but it is not known for how long a person may be contagious before or after symptoms appear.
The hallmark symptoms are:
Fever greater than 100.4 degrees F (38.0 degrees C)
Other breathing symptoms
The most common symptoms are:
Chills and shaking
Cough -- usually starts 2-3 days after other symptoms
Less common symptoms include:
Cough that produces phlegm (sputum)
Nausea and vomiting
In some people, the lung symptoms get worse during the second week of illness, even after the fever has stopped.
Signs and tests
Your health care provider may hear abnormal lung sounds while listening to your chest with a stethoscope. In most people with SARS, changes on a chest x-ray or chest CT show pneumonia, which is typical with SARS.
Rapid polymerase chain reaction (PCR) test for SARS virus
All current tests have some limitations. They may not be able to easily identify a SARS case during the first week of the illness, when it is most important.
People who are thought to have SARS should be checked right away by a health care provider. If they are suspected of having SARS, they should be kept isolated in the hospital.
Treatment may include:
Antibiotics to treat bacteria that cause pneumonia
High doses of steroids to reduce swelling in the lungs
Oxygen, breathing support (mechanical ventilation), or chest therapy
In some serious cases, the liquid part of blood from people who have already recovered from SARS has been given as a treatment.
There is no strong evidence that these treatments work well. There is evidence that the antiviral medication, ribavirin, does not work.
The death rate from SARS was 9 to 12% of those diagnosed. In people over age 65, the death rate was higher than 50%. The illness was milder in younger patients.
Many more people became sick enough to need breathing assistance. And even more people had to go to hospital intensive care units.
Public health policies have been effective at controlling outbreaks. Many nations have stopped the epidemic in their own countries. All countries must continue to be careful to keep this disease under control. Viruses in the coronavirus family are known for their ability to change (mutate) in order to spread among humans.
Calling your health care provider
Call your health care provider if you or someone you have been in close contact with has SARS.
Reducing your contact with people who have SARS lowers your risk for the disease. Avoid travel to places where there is an uncontrolled SARS outbreak. When possible, avoid direct contact with persons who have SARS until at least 10 days after their fever and other symptoms are gone.
Hand hygiene is the most important part of SARS prevention. Wash your hands or clean them with an alcohol-based instant hand sanitizer.
Cover your mouth and nose when you sneeze or cough. Droplets that are released when a person sneezes or coughs are infectious.
Do not share food, drink, or utensils.
Clean commonly touched surfaces with an EPA-approved disinfectant.
In some situations, masks and goggles may be useful for preventing the spread of the disease. You may use gloves when handling any items that may have touched infected droplets.
McIntosh K, Perlman S. Coronaviruses including severe acute respiratory distress syndrome (SARS)-associated coronavirus. In: Mandell GL, Bennett JE, Dolin R, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Disease. 7th ed. Philadelphia, Pa: Saunders Elsevier; 2009:chap 155.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and Denis Hadjiliadis, MD, Assistant Professor of Medicine, Division of Pulmonary, Allergy and Critical Care, University of Pennsylvania, Philadelphia, PA. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.