Meanwhile, the U.N. agency lifted a month-old warning to avoid nonessential travel to Taiwan, underscoring claims of success in the global fight against the illness. The only such warning still in effect is for Beijing.
Gro Harlem Brundtland, the WHO Director-General, told a conference that the world has stopped the spread of severe acute respiratory syndrome in the nearly 100 days since international health authorities sounded the first global alert.
"We have seen SARS stopped dead in its tracks," Brundtland told more than 1,000 international researchers, officials and health experts meeting in Kuala Lumpur to discuss lessons learned from the outbreak.
The spread of the pneumonia-like disease by air travel highlighted the dangers of an infectious outbreak in the globalized age, she said. Nations that fail to make prompt, open disclosures risk their international credibility, she added.
Brundtland did not point a finger directly at China, but she was clearly referring to Beijing's initial attempts to downplay its outbreak, which led to a shake-up at its Health Ministry. Brundtland praised China's "change in opinion about what was necessary."
Travel advisories have been lifted for several Chinese provinces, but there was no indication when Beijing might be cleared. The capital still has many SARS cases, senior WHO officials said, though they consider the outbreak to be largely contained.
David Heymann, WHO executive director on communicable diseases, said the question of a big SARS reappearance depends largely on China, where it originated. Chinese officials acknowledge at least 5,327 probable cases and 346 deaths as of Monday.
"China certainly is the key to this outbreak in many respects," Heymann said. "Particularly because China has been able to contain this outbreak."
SARS has killed about 800 people and sickened more than 8,400 since first being detected in southern China in November. New cases spiked in March and April, but have plunged in recent weeks.
Dr. Paul Gully, director general of Canada's health department, said even heightened surveillance and rapid response mechanisms introduced after SARS broke out in Toronto weren't enough to prevent a second cluster of cases in late May.
"It's really apparent that the ember can continue to smolder and the disease recur," Gully told the conference.
Gao Qiang, China's vice minister of health, acknowledged that China's initial response to the SARS outbreak was "inadequate." He refused to comment on the travel warning for Beijing, but showed diplomatic goodwill to Taiwan, something rare between the bitter rivals.
"I would like to congratulate them, because we are all Chinese," Gao told reporters. "It's good for the recovery of Taiwan's tourism industry and economic development."
After mainland China and Hong Kong, Taiwan was hit hardest SARS, racking up 697 cases, including 83 deaths.
Taiwan was attending its first WHO event in 30 years. The island's membership has long been blocked by China, which regards Taiwan as part of its territory following a split amid civil war in 1949. Beijing opposes any bid by the self-governing island to join international organizations.
Last week, WHO rejected two Taiwanese requests to be dropped from its travel warning list. Some Taiwanese officials suspected that China was trying to pressure WHO to take Beijing and Taiwan off at the same time.
"If the travel advisory was not removed, Taiwan's economy could not stand much longer," said Dr. Su Ih-jen, Taiwan's director of disease control.
SARS will not be the last unusual disease to strike humans, health officials said. The recent U.S. outbreak of monkeypox should be a warning, said Dr. James Hughes, director for infectious diseases at the U.S. Centers for Disease Control.
Hughes said the prairie dog had been identified as the likely source of the outbreak, probably picking it up from imported animals from Africa. No one has died of the disease since it was detected in the United States last month, but at least 15 people have been infected.
By Patrick McDowell