Severe acute respiratory syndrome (SARS) a contagious and sometimes fatal respiratory illness first appeared in China in November 2002. Since then, the disease has spread worldwide, infecting thousands of people and resulting in more than 800 deaths.
There has been one near pandemic to date, between the months of November 2002 and July 2003, with 8,096 known infected cases and 774 deaths (a case-fatality rate of 9.6%) worldwide being listed in the World Health Organization's (WHO) 21 April 2004 concluding report.
Mortality by age group as of 8 May 2003 is below 1% for people aged 24 or younger, 6% for those 25 to 44, 15% in those 45 to 64 and more than 50% for those over 65. For comparison, the case fatality rate for influenza is usually around 0.6% (primarily among the elderly) but can rise as high as 33% in locally severe epidemics of new strains. The mortality rate of the primary viral pneumonia form is about 70%.
The disease has spread worldwide, infecting thousands of people and resulting in more than 800 deaths. The rapid and unexpected spread of SARS alarmed both health officials and the public.
SARS the first newly emerged, serious and contagious illness of the 21st century illustrates just how quickly infection can proliferate in a highly mobile and interconnected world.
It's likely the disease began with a single infected person, and then spread around the globe through unsuspecting travelers.
SARS is particularly troubling because health experts know so little about it. Scientists do know that the cause is a new type of coronavirus one of a family of viruses that in humans usually cause mild upper respiratory infections, including common colds. How the new coronavirus evolved or why it turned deadly isn't known. Nor is it clear why some people succumb to the disease and others recover. Although many who died were older adults with other health problems, SARS has also proved fatal in healthy, young adults. Adding to the uncertainty is that the symptoms are similar to those of other respiratory illnesses.
Because of the high amount of uncertainty about SARS, health officials quickly put into place an intensive global campaign to control the disease. That campaign, spearheaded by the World Health Organization (WHO), proved so successful that by July 2003 SARS had been effectively contained worldwide, and all SARS-related travel restrictions had been lifted.
That doesn't mean the disease has been eradicated, however. In 2004, some SARS cases surfaced in China.
Signs and symptoms of SARS
Initial symptoms are flu-like and may include: fever, myalgia, lethargy, gastrointestinal symptoms, cough, sore throat and other non-specific symptoms. The only symptom that is common to all patients appears to be a fever above 38 degree C (100.4 degree F). Shortness of breath may occur later.
Treatment of SARS
Antibiotics are ineffective as SARS is a viral disease. Treatment of SARS so far has been largely supportive with antipyretics, supplemental oxygen and ventilatory support as needed.
Suspected cases of SARS must be isolated, preferably in negative pressure rooms, with complete barrier nursing precautions taken for any necessary contact with these patients.
There was initially anecdotal support for steroids and the antiviral drug ribavirin, but no published evidence has supported this therapy.
Researchers are currently testing all known antiviral treatments for other diseases including AIDS, hepatitis, influenza and others on the SARS-causing coronavirus.There is some evidence that some of the more serious damage in SARS is due to the body's own immune system overreacting to the virus - a cytokine storm. Research is continuing in this area.
Doctors and health officials worry that an outbreak of the disease may occur again. The sense of concern surrounding SARS remains because as yet there's no known treatment.