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Scientists Establish Source of SARS - 2003-09-05


There is fresh evidence that wild animals sold in Southern Chinese food markets helped pass Severe Acute Respiratory Syndrome to humans, and that a reservoir of the disease still exists. Researchers compared the genetic sequence of viruses found in certain animals to those found in SARS patients.

Scientists at Hong Kong University and at the Guangdong Center for Disease Control first detected a possible SARS virus in wild animals in late May. They named as possible carriers raccoon dogs, ferret badgers and civets, with civets the most likely culprit.

Subsequent research by the same scientists, published Thursday in the latest edition of the journal Science, concludes that SARS probably did jump from the civet to humans while the animal was being handled or prepared for cooking.

Microbiologist Dr. Guan Yi of Hong Kong University spoke to reporters on Friday.

"He says that many market workers [who handled civets] have antibodies similar those found in people who suffered from SARS, even though the butchers and animal traders who tested positive for the antibodies do not recall feeling ill," he said.

The first known SARS cases emerged in November of last year in Southern China, where a wide variety of wild animals is a regular part of the human diet. The disease then spread in just six months to more than 8,000 people in 31 countries, and more than 900 people died from the disease.

While quarantines, travel advisories and extensive hygiene programs helped interrupt the spread of the disease, health authorities worry that the source of the virus still exists, and that new outbreaks could erupt in the coming months.

Scientists say the disease is caused by a coronavirus. Patients with SARS typically suffer from a serious and potentially deadly form of pneumonia.

The head of Hong Kong University's Microbiology department, Dr. K.Y. Yeun, says the new research proved that the coronavirus found in civets was almost identical to that found in SARS patients.

Given existing stocks of civets, Dr. Yeun says this is the best evidence yet that a reservoir of the coronavirus still exists and a new SARS outbreak could occur at any time.

After the initial findings in May, authorities in Southern China prohibited the sale of wildlife in markets - civets included - but the ban has since been lifted.

Many scientists now suggest the ban's removal was premature, and risky.

A team of World Health Organization officials who recently toured southern China in search of clues to the origins of SARS said farm animals such as cows, pigs, chickens and sheep do not carry the coronavirus associated with the disease.