http://www.nytimes.com/2003/05/23/science/sciencespecial/23CND-CAT.html?ei=5070&en=6932c5d0e2855ddb&ex=1054872000&pagewanted=print&position=

May 23, 2003

Scientists Find Animal Link for SARS Virus

By KEITH BRADSHER and LAWRENCE K. ALTMAN

ONG KONG, May 23 — A virus virtually identical to the one believed to cause SARS in humans has been found in a catlike tree-dwelling animal whose meat is a delicacy in southern China and in two other species, scientists here and at the World Health Organization said today.

Discovery of the virus in animals makes it much more unlikely that SARS can be eradicated, because of the difficulty of eradicating the animals that harbor the virus. But control of those species could reduce the risk of it from seeding cases into the human population in the future.

W.H.O. officials said scientists had obtained 25 specimens from eight species of animals from a market in Shenzhen, just across the Hong Kong border in mainland China. The SARS virus was found in six masked palm civets — the catlike animal that is served as food — and in the only raccoon dog tested. Evidence of the infection was also found in antibodies from the blood of a badger.

Health officials had previously said that the first cases of the disease appeared to have occurred last November among people involved in the culinary preparation of rare animals in Foshan, 90 miles up the Pearl River from here.

Yuen Kwok-yung, a microbiologist at Hong Kong University, said the disease appeared likely to have jumped to people from civets, but that the civets could have contracted the virus from another species. W.H.O. officials said transmission theoretically could have gone from humans to civets.

Feces from a "very high" proportion of civets have tested positive for a virus that appears to be genetically very similar to the corona virus that has been linked to severe acute respiratory syndrome in people. A low proportion of animals from other species have also tested positive, Professor Yuen said.

The virus could have been transmitted from one species of animals to the others in the markets, W.H.O. said.

Civets are grown on farms in Guangdong province and are sometimes trapped in the wild for Chinese kitchens. The animals are becoming increasingly rare across their range, from Pakistan to Indonesia, because of deforestation, and their sale is banned in Hong Kong, where they are a protected species.

Professor Yuen added that it remains possible the virus occurs in other species as well, and the virus might even be capable of infecting household cats, which could make disease control more difficult.

"The animal source is very important because you want to stop further jumping" between species, he said.

A Chinese medical professor who had been treating infected patients brought the disease from neighboring Guangdong province to Hong Kong, Asia's busiest transportation hub, in late February. Travelers from Hong Kong then carried the disease to Beijing, Taiwan, Singapore, Vietnam and Canada.

Masked palm civets — which are not cats, despite the name civet cats — have short fur that can be brown, orange, red or gray, with black bands on the head and feet. They eat mostly fruit, weigh up to 13 pounds and have bodies that grow up to two-and-a-half feet long, with tails of nearly equal length.

Judging from their activity and feeding habits, infected civets do not appear to feel any ill effects from the virus, Professor Yuen said.

While no tests have been done, it is also "theoretically possible" that household cats could become infected, as they are very similar biologically to civets, Professor Yuen added. "It is theoretically possible it would also infect household cats because they are very near in biological relatedness" to civets, he said.

The raising and slaughter of civets and other exotic animals should be strictly regulated to prevent further outbreaks of SARS and possibly other new diseases, he said. But a total ban on consumption of them is unlikely to succeed because the consumption of wild animals is so much a part of Chinese culture, he contended.

"It is very difficult to stop a culture, it has been there for 5,000 years," Professor Yuen said.

Dick Thompson, a spokesman for W.H.O., said that Chinese officials said they were about to ban the sale of the species in markets.

There are small differences between the virus found in civets and the corona virus found in people, raising the possibility that a small mutation in the virus while it was still in the cats had made the disease more transmissible to people. "Maybe recently, it has some mutation and then it jumps into humans," Professor Yuen said.

Hong Kong University conducted its research with Shenzhen's Center for Disease Control and Prevention. Hong Kong University officials had been waiting for a medical journal to publish their research, but felt compelled to hold a news conference this afternoon when Shenzhen officials announced the research today on their side of the border.

It is unlikely that diners can contract the disease from well-cooked animals of any type, Professor Yuen said. The rearing, slaughter and preparation of infected animals are activities more likely to transmit viruses across species, he added.

Copyright 2003 The New York Times Company