FRIDAY, May 9, 2003 (HealthDayNews) -- The SARS virus hasn't undergone any major mutations as it has spread through countries around the world, say scientists who studied the genetics of cultured SARS viruses from five different sources.
But the research, published online by The Lancet, also says the SARS virus could pose a threat to humans for many years, BBC News Online reports.
The fact that scientists found no major genetic mutations in the virus is encouraging. If the virus is stable, that increases the chances of developing a vaccine to fight it. It also means that any SARS vaccine is likely to remain effective for a long time, researchers say.
On the negative side, the lack of major mutations means the SARS virus isn't weakening as it moves through successive generations. Some scientists had hoped the illness caused by the virus would become less severe over time as the virus spread, The New York Times reports.
The scientists who did the study suggest the virus doesn't need to evolve rapidly because it's well adapted to resisting attack by the human immune system, says BBC News Online.
Another new study from University of Hong Kong researchers says that much of the lung damage found in SARS patients is actually caused by the body's immune system responding in an overblown way to the presence of the virus.
As researchers try to better understand the nature of the virus, authorities in China and other countries continue to struggle with the effects of the highly infectious respiratory disease.
There was some positive news in China, the epidemic's epicenter. Hundreds of teachers, students and workers were released Thursday from two weeks of quarantine at a central Beijing university.
In another show of optimism, Chinese officials say they'll let 80,000 students come to Beijing next month to take college entrance exams, the Associated Press reports.
And National Basketball Association star Yao Ming will host a live telethon this weekend in Shanghai to raise money for SARS research and treatment.
Less encouraging was acknowledgment by Chinese health officials that they're unable to trace at least 60 percent of new SARS cases in Beijing back to the source of infection, Voice of America News reports.
That inability to track all the people with SARS raises new concerns about how health officials will be able to contain the outbreak. That could be disastrous. Chinese authorities have said rural areas of the country are incapable of coping with SARS if it spreads outward from Beijing.
"According to our statistics, 40 percent of the newly received SARS patients have been in quarantine or under medical observation. But for the rest of the patients, we do not know how they got infected. We do not know where they got infected. They just popped up in the hospital as confirmed SARS patients," Liang Wannian, deputy chief of Beijing's Health Administration, told Voice of America News.
China reported six more SARS deaths and 118 new cases Friday. So far, 230 people have died in China and a total of 4,805 have been infected.
Around the world, about 7,100 people have been infected and 515 have died from SARS.
Taiwan reported 18 new SARS cases Friday. That's the largest single-day increase there since the SARS outbreak started on the island two months ago.
Hong Kong on Friday reported its lowest one-day increase -- two deaths and six new cases -- since the start of the epidemic there.
Along with the mounting human toll, SARS could pose a serious threat to Asia's economic health. The Asian Development Bank estimates the disease could cost Asia $28 billion in lost economic output, BBC News Online reports.
About $20 billion of that lost economic output could occur in four countries -- China, Hong Kong, South Korea and Taiwan, the bank estimates.
The Asian economic losses would be caused by a number of factors, including a falloff in consumer confidence, a drop in tourism, and a decline in investment and government revenues. Many companies have temporarily closed their Asian operations, and tourism to some areas has dropped by 50 percent or more, BBC News Online reports.
More information
To learn more about SARS, visit the World Health
Organization or the U.S. Centers for
Disease Control and Prevention.
