A US scientist has told the American Association for the Advancement of Science conference that the deadly SARS (Severe Acute Respiratory Syndrome) virus has been contained so effectively that it may be considered eradicated.

Kathryn Holmes, professor of Microbiology at the University of Colorado, said she is confident that SARS no longer exists in the wild and has essentially disappeared as a threat. She was reported by The Times on Monday as saying that the epidemic strain has not been seen in nature since June 2003.

She also said that China's Himalayan palm civets, thought to be the most likely source of the SARS virus, have been wrongly blamed, and do not harbor the epidemic strain. If SARS were to return as a threat, it would have to evolve again from scratch or be released in a laboratory accident or bio-terror attack, she said.

However, experts from China, where the epidemic first broke out, say such a conclusion is too optimistic, since scientists haven't yet identified the real source of the virus.

"It is too early to say that the corona virus, which caused the SARS epidemic, does not exist in the wild any longer because up to now experts have failed to find the origin of the virus at all," said Liu Qiyong.

Liu, a leading expert from the Chinese Center for Disease Control and Prevention, has conducted research into its source since the outbreak of the epidemic in 2003.

Liu added that he and his group have found the same SARS virus in Himalayan palm civets and many other wild animals since early 2004.

No evidence can prove that the palm civet was the source of the virus, or only an "amplifier," making it spread more widely, Liu said.

However, Liu admitted that he has failed to find the virus in any wild animals since June 2004.

This view was echoed by Roy Wadia, a World Health Organization spokesperson in Beijing, who believed that the virus still exists "out there" -- probably still in a species of wild animal (not necessarily the civet) -- and could therefore "resurface" at any time.

He recalled the Ebola virus, which appeared to emerge out of nowhere in central Africa, and claimed many lives before vanishing and re-emerging after several years.

He also pointed out that biosafety standards at laboratories that carry out work on the SARS corona virus need to be strengthened not only in China but also around the world.

"We still do not have a SARS vaccine for the general population, although trials are going on in China and the US," said Wadia. "SARS can still pose a threat, and should be taken very seriously."

(China Daily February 23, 2005)