U.S. researchers recreate SARS virus

WASHINGTON, Nov. 25 (Chinese media) -- Researchers at

University of North Carolina and Vanderbilt University have synthetically

reconstructed the bat variant of the SARS coronavirus (CoV) that caused the SARS

epidemic in 2003.

The scientists say designing and synthesizing the

virus is a major step forward in their ability to find effective vaccines and

treatments for any strain of SARS virus that might affect humans in the future.

A report of the work was published Tuesday in the

Proceedings of the National Academy of Sciences.

"Only three other teams of researchers have

synthetically reconstructed a virus. In this case we reconstructed the likely

progenitor of the SARS-CoV epidemic," said Ralph Baric, one of the leaders on

the project. "The bat SARS virus is about four times larger than any other virus

that has been synthesized to date. It will allow us to test the pathways in

which the virus emerges and understand the ways that animal coronaviruses move

from one species to another."

SARS is believed to have first emerged humans in Asia

in late 2002. Over the next several months, the illness spread to more than two

dozen countries before the global outbreak was contained.Of the more than 8,000

people worldwide who were diagnosed with SARS in 2003, 774 died.

Baric said SARS is believed to have originated in

bats, and "jumped" to humans either directly or through raccoon dogs and palm

civets.

"Although the strains associated with the 2002-2003

epidemic no longer circulate in humans, the animal precursor strains are common

and will likely re-emerge in the future," he said. "The key problem is that many

of the vaccines and therapeutics targeting the 2002-2003 epidemic strains may

not work against future emergent strains."

Baric said synthesizing the SARS co-variant that

infects bats and then modifying it so that it can grow well in laboratory

animals will allow researchers to search for vaccines and treatments that would

be effective against any strain of SARS that might infect humans in the future.

Viruses that start in animals and mutate to infect

humans tend to be slightly different each year. An example is the influenza

virus, which is different each year and requires a different vaccine each year

to provide immunity.

The value of the research goes beyond SARS, he added.

"Potentially, we can apply this technology to many other emerging viruses," he

said.