Severe Acute Respiratory Syndrome
Severe acute respiratory syndrome (SARS) was first detected in the Guangdong province of China in late 2002. It has since spread to at least 17 countries, mainly in Southeast Asia, but also to Canada and the United States. Overall, about 10 to 15% of people with SARS die, although the risk of death varies with the patient's age and access to advanced medical care. People older than 60 years are much more likely to die. No deaths have occurred in the USA.
SARS appears to be caused by a new type of coronavirus. Other coronaviruses cause common colds or infect various animals. Transmission of SARS occurs through face-to-face personal contacts, such as health care workers; family members; and people in nearby seats on airplanes or beds in hospitals. Because other infections transmitted in a similar fashion are spread by contact with secretions from the respiratory tract (such as the lungs or possibly the nose or throat), SARS probably spreads in the same way. A person becomes infected when his hands touch secretions from a person who is infected and he then touches his nose, mouth, or eyes, or when he inhales such secretions. However, some people who have developed SARS may not have had face-to-face contact, and many people who have face-to-face contact with people infected with SARS do not catch the illness. The virus is also in stool, and some people appear to have been infected after coming into contact with water supplies contaminated with sewage.
Symptoms and Diagnosis
Symptoms begin about 2 to 10 days after catching the infection. The first symptoms resemble those of other more common infections and include fever, headache, chills, and muscle aches. Runny nose and sore throat are unusual. About 3 to 7 days later, dry cough and difficulty breathing may develop. Most people recover within 1 to 2 weeks. However, about 10 to 20% develop severe difficulty breathing, resulting in insufficient oxygen in the blood; worldwide, about half of these people need assistance with breathing. Few people in the USA have had symptoms this severe. If a person dies, it is because of breathing difficulty.
SARS is not suspected unless a person may have been exposed to someone who has the infection and also has fever plus a cough or trouble breathing. A person may have been exposed if, within the previous 10 days, he has traveled to an area where SARS is relatively common or had face-to-face contact with a person who may have SARS. SARS is relatively common in the Peoples' Republic of China (both Mainland China and Hong Kong); Hanoi, Vietnam; and Singapore. People who get SARS in areas where it is uncommon are usually direct household contacts, such as family members, or health care workers.
If a doctor suspects that a person may have SARS, an x-ray of the chest is usually done. Swabs from the person's nose and throat may be taken to try to identify the virus. Examination of a sample of the person's sputum may be necessary. Blood is tested for SARS infection when the illness is first recognized and again 3 weeks later. If there is difficulty breathing, other blood tests may be needed.
Prevention and Treatment
Travel advice from the Centers for Disease Control and Prevention (CDC) should be heeded. Wearing a mask is not recommended except for those who are in close contact with someone who may have SARS. People exposed to others who may have SARS (for example, family members, airline personnel, and health care workers) should be alert for symptoms of illness. If they have no symptoms, they may attend work, school, and other activities as usual. If they develop fever, headache, chills, muscle aches, cough, or difficulty breathing, they should avoid face-to-face contact with other people and seek medical attention.
If doctors think a person might have SARS, the person should be quarantined in a room with a ventilation system that limits the spread of microorganisms in the air. Although some books and films depict quarantine as involving an unduly ascetic and depressing lifestyle for prolonged periods of time, quarantine for possible SARS should be needed for only a few days and involves no major deprivation. If, within 72 hours of beginning quarantine, symptoms do not progress to indicate SARS, the person is usually free to resume normal activities. Health care workers who care for people who may have SARS wear masks, goggles, gowns, and gloves.
Doctors may try treating SARS with antiviral drugs, including oseltamivir and ribavirin, and corticosteroids. However, there is no evidence that these or any other drugs are effective. The virus eventually disappears. People with mild symptoms need no specific treatment. Those with moderate difficulty breathing may need to receive oxygen by plastic nasal prongs or a face mask. Those with severe difficulty breathing may need mechanical ventilation to aid breathing. Research now is focused on developing a test for rapid diagnosis, effective therapies, and a preventive vaccine.
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