What is SARS?
Severe acute respiratory syndrome (SARS) is a viral respiratory illness that was first reported in Asia in February 2003. In early March, the World Health Organization (WHO) issued a global alert about SARS. Over the next few months, the illness spread to more than two dozen countries in North America, South America, Europe, and Asia. By late July, however, no new cases were being reported and the illness was considered contained. According to WHO, 8,098 people worldwide became sick with SARS during this outbreak; of these, 774 died. For more information, check the WHO SARS Web site or visit other pages on CDC's SARS Web site.
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 (hypoxia) in which insufficient oxygen is getting to the blood. In 10 percent to 20 percent of cases, patients require mechanical ventilation. Most patients develop pneumonia. For more information, see the MMWR dispatch that describes the clinical features of SARS.
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. For more information about the SARS coronavirus, click here.
How is SARS spread?
The primary way that SARS appears to spread is by close person-to-person contact. The virus that causes SARS 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 in the context of the SARS outbreak?
Close contact is defined in the CDC SARS case definition 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 sitting across a waiting room or office for a brief time.
If I were exposed to SARS, how long would it take for me to become sick?
The time between exposure to the SARS virus and 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.
How long is a person with SARS infectious to others?
Available information suggests that people with SARS are most likely to be infectious only when they have symptoms, such as fever or cough. However, as a precaution against spreading the disease, CDC recommends that people with SARS limit their interactions outside the home (for example, by not going to work or to school) until 10 days after their symptoms have gone away. Patients are most infectious during the second week of illness.
Do some people who recover from SARS become sick again or relapse?
At this time we do not have a full understanding of the natural course of illness in persons infected with SARS-CoV. It will be important to learn what factors might influence illness progression and recovery. Such factors could be related to the virus itself, how the body's immune system reacts to the virus, how infection with the virus is treated, or other possibilities. CDC and other scientists are trying to learn the answers to these important questions.
What medical treatment is recommended for patients with SARS?
CDC recommends that patients with SARS receive the same treatment that would be used for any patient with serious community-acquired atypical pneumonia. SARS-CoV is being tested against various antiviral drugs to see if an effective treatment can be found.