Severe Acute Respiratory Syndrome/SARS,

Severe Acute Respiratory Syndrome (SARS),
contagious respiratory illness that can cause a fatal form of pneumonia. The illness first appeared in November 2002 in people living in Guangdong province in southern China. Its cause was unknown and available treatments were ineffective. By February 2003 new cases of the illness were reported in Hong Kong, Vietnam, Singapore, and Canada. The fast spread of the disease, its deadly nature, and its unknown cause prompted the World Health Organization (WHO), an agency of the United Nations, to issue a global alert in March 2003 designating SARS as a worldwide health threat. The alert triggered governments around the world to establish infection-control procedures to prevent the illness from reaching epidemic proportions. Despite these public-health measures, by mid-May 2003 more than 7,600 SARS cases had been reported in 29 countries and the disease had caused more than 580 deaths.

II  Symptoms And Treatment, 

SARS symptoms begin with a fever about 38°C (about 100.4°F) or higher, chills, headache, and malaise. Two to seven days later some people develop a dry cough and difficulty breathing. Symptoms may progress to a severe form of pneumonia, in which air sacs in the lungs fill with fluid, preventing oxygen from reaching blood cells and nourishing the other cells of the body. Aside from regular nursing care and the use of a respirator to help breathing in severe cases, there is no effective treatment for SARS. Recovery seems to depend on the health of the patient’s immune system. Epidemiologists (scientists that study the cause and spread of diseases) are still collecting information about SARS, but early data indicate that those most susceptible to the fatal form of the illness are aged 40 or older and have a history of a chronic disease.

III  How The Illiness Spreads,

Infection with SARS results from close contact with an infected person. SARS can spread if a person inhales droplets sprayed into the air when an infected person coughs or sneezes. SARS may also spread when a person touches an object that has been contaminated. Scientists are investigating if the infection can spread in other ways. Symptoms typically develop two to seven days after exposure, so someone may unknowingly become infected and spread the illness before developing symptoms. In Asia, before infection-control measures were established, many SARS cases occurred among hospital workers who cared for SARS patients. These infected hospital workers, in turn, spread the illness to people living in their households. Most SARS cases reported in the United States and Canada were in people who became infected with the illness while traveling abroad or people who were exposed to infected travelers from abroad.

IV  Cause, 

Although studies are incomplete, scientists suspect that a newly discovered virus from the coronavirus family causes SARS. Until now coronaviruses have been known to cause only minor illnesses in humans, such as colds or diarrhea. The SARS virus is unique from other coronaviruses because it has undergone a series of genetic mutations (changes) to acquire properties that cause severe illness in humans. Once scientists are certain that they have identified the cause of the disease, they can develop diagnostic tests that will help identify people with SARS. A diagnostic test would also help epidemiologists determine how long someone infected with SARS remains contagious and if those infected develop long-term immunity to the disease. Understanding the cause will help scientists develop new treatments that prevent the illness or lessen its severity.

V  Prevention, 

Until effective treatments can be developed, public-health officials have established infection-control measures to contain the spread of SARS. Those people diagnosed with SARS or suspected of having the illness are treated in isolation in their homes, in hospitals, or in other designated health-care settings. Caregivers follow strict procedures to lessen their own risk of infection. In April 2003 public-health officials in a number of countries imposed quarantines to restrict the movements of people who were exposed to the SARS virus. The WHO also issued travel advisories recommending against nonessential travel to certain countries where the risk of infection was high.