The newest developments came as the U.S. government ordered 48 Web sites to stop promoting bogus ways to prevent and treat the deadly disease, and health officials urged Americans to beware of quacks preying on their fears.
Five deaths in China, four in Taiwan and two in Hong Kong boosted the worldwide SARS death toll to 526 Saturday. More than 7,200 people have now been infected in 25 countries.
Following China's admission Friday that health officials were unable to trace the source of infection for at least 60 percent of new SARS cases in Beijing, the World Health Organization expressed serious new doubts about the fight against SARS there.
"We have a whole load of people, and we don't know where they got the disease," WHO spokeswoman Mangai Balasegaram told The Associated Press . "The problem with the data is that there are holes in it."
And that means, she added, that "you don't understand what's going on. The epidemic might be flying off in one direction, and you might not know about it."
While many tough anti-SARS measures remain in place in China -- where 230 people have died and thousands have been hospitalized or isolated -- Beijing authorities have been upbeat in recent days because their data shows a slowing of new infection rates, MSNBC reports.
Officials lifted quarantines on six hospitals, two residential communities and four construction sites where SARS cases had been found, and are allowing 80,000 students to gather in Beijing next month for college entrance examinations.
On Saturday, China reported five deaths and another 85 infections. The death toll there is now 235; the number of cases, 4,884.
Taiwan reported 23 new cases, its biggest one-day jump since the outbreak began there two months ago, AP reports.
During the early stages of the epidemic, Taiwan was able to quickly trace and isolate the infection sources, many of whom were people who had recently visited China and Hong Kong. But recently, SARS has begun spreading rapidly within communities. So far, 18 people have died and 172 sickened.
Authorities sealed off a housing complex where one resident died of the virus, while one of the largest department stores in Taipei was closed for a major disinfection following the infection of a cashier and the quarantining of 175 employees.
The U.S. State Department now says Americans residing in Taiwan may wish to consider leaving.
Meanwhile, U.S. regulators warn that Internet sites that don't cease illegal SARS marketing face seizure of their products along with prosecution and fines, AP reports.
The officials said the Web sites were illegally claiming that dietary supplements, ranging from vitamin C and oregano oil to colloidal silver and belladonna, can treat or cure SARS. Other sites promise SARS "protection kits" that include personal air purifiers, gloves, masks and alcohol wipes.
Scientists have yet to find a cure for the deadly respiratory illness.
"Scam artists follow the headlines, trying to make a fast buck with products that play off the news," said Howard Beales of the Federal Trade Commission, which conducted the crackdown along with the Food and Drug Administration.
Many of the same products also were advertised as anthrax defenses during the 2001 bioterrorist attack, and the government cracked down then, too.
In other developments Saturday:
- Canadian health officials said the city of Toronto, hardest-hit outside of Asia, has had no new reported SARS cases since late April, and could be declared SARS-free as soon as next week.
- Hong Kong reported only two deaths -- the lowest daily infection increase so far and a further sign the disease may be on the wane in the territory, after killing 212 people there.
- Singapore plans to start electronically tracking every person entering a public hospital in an effort to curb the spread of the disease there.
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