Chinese scientists have traced the severe acute respiratory syndrome (SARS) virus back to a similar virus found in the civet cat and the raccoon dog, both animals found in the wild in China and elsewhere.

Three strains of SARS-like virus isolated from samples of six palm civets and a raccoon dog were similar to the human SARS virus, and sequencing of their genes indicated the animal virus was the precursor to the human form, said Zhuang Zhixiong, director of Shenzhen Disease Control and Prevention Center.

Zhuang said a group of scientists from Shenzhen and neighboring Hong Kong had searched for animals affected by SARS to determine the relation between animal and human SARS viruses before locating the possible source of human SARS virus.

During the research, they focused their attention on mammals, including the palm civet, coypu, raccoon dog, cat, rabbit and three other animals, said the director.

The gene sequencing showed 99 percent of the animal virus and human SARS virus was homologous, or similar in structure.

The scientists also tested 10 dealers of wild animals for the SARS antibody, and found five were positive, said the director.

The result indicated the SARS virus in wild animals might be able to infect those in close contact with them.

The director said the findings provided clues for scientists to determine the original sources of SARS virus and how it spread.

(Xinhua News Agency May 24, 2003)