Despite some claims during the spread of the outbreak of the disease, it seems no one knows -- further studies are still needed before a final conclusion can be made.

"Studies on the SARS virus and the causes are very difficult and complicated. It is hard to approach a final and correct finding within just two or three months,'' an official with the Key Science and Technology Group under the National Task Force for SARS Control and Prevention told China Daily.

"Also it is hard to say which results are authoritative, because many Chinese scientists, as well as foreign scientists, are still conducting their studies,'' said the official, who declined to be named.

Researchers from China Agricultural University have found that masked palm civets, which have been regarded as the biggest suspects over the past month, do not have the coronavirus linking it with SARS, the Beijing Youth Day reported Friday.

Their finding is based on studies of 732 samples of wild animals, which were collected from Beijing, Guangdong and another five areas.

The samples came from 54 types of wild animals and 11 types of domesticated animals, including masked palm civets, bats, monkeys and snakes.

Through an internationally-used diagnostic test on the samples, researchers at the university have concluded that the animals are not the origin of the human SARS coronavirus.

"If the SARS virus really came from masked palm civets, the number of SARS patients in the country would be much larger,'' said the university's Vice-President Sun Qixin, who went to the Dongmenwai Market in Shenzhen to collect animal samples.

Sun said the coronavirus detected in masked palm civets shares only 77.7 percent of the genetic code of the human SARS coronavirus.

But experts in Hong Kong said it is more than 99 percent similar. They also looked at animals from the Shenzhen market, announcing on May 23 that the potentially deadly virus is caused by the coronavirus found in masked palm civets.

(China Daily June 21, 2003)