Sept. 30 (Bloomberg) -- Bats that harbor viruses similar to the one that causes SARS may be the ultimate source of the lung disease that killed almost 800 people from late 2002 through 2003, according to a study in Sciencexpress, the online version of Science magazine.

As much as 71 percent of groups of bats trapped in the Guangxi and Hubei provinces of China were infected with SARS-like viruses, called coronaviruses, said researchers led by Wendong Li of the Institute of Zoology and Chinese Academy of Sciences in Beijing.

Disease trackers who found that animals sold for food called civet cats may have spread SARS, or severe acute respiratory syndrome, to people have said that they might not have been the source of the virus. Bats harbor a number of diseases that can spread to humans, and the study suggests they may have provide a breeding ground for additional SARS-like infections, the study said.

The findings present ``a new challenge to the diagnosis and treatment of future disease outbreaks since the current test and therapeutic strategies may not work effectively against all viruses in this group,'' the authors concluded.

The study looked at 408 bats from nine different species that were collected from March to December of 2004 in four provinces, including Guangdong and Tianjin. Using genetic screening, the researchers found that 13 of 46 bats, or 28 percent, from one location and two of six, 33 percent, from another location in Guangxi were infected with SARS-like viruses. At one location in Hubei, five of seven bats, or 71 percent, were infected.

Asia, where people and animals often live in close proximity, has frequently functioned as a viral ``melting pot'' where a number of diseases have crossed the species barrier. Researchers at the World Health Organization are working to stop human infections of a lethal strain of bird flu called H5N1.

At least 60 of 116 people infected with bird flu have died, according to the World Health Organization. The international health agency criticized China's plan to combat bird flu this week, saying it isn't comprehensive and lacks detailed planning.

Companies are working to develop prevention and treatment measures for the SARS virus, should it return. Intradigm Corp., the closely held maker of gene-blocking drugs, said a study showed its experimental inhaled medication slowed life-threatening SARS infections in monkeys.

The drug uses a technology called RNA interference to stop the SARS virus from making proteins used to infect cells and reproduce, said Patrick Lu, Intradigm's executive vice president for drug development and a study co-author.

To contact the reporter on this story: John Lauerman in Boston at jlauerman@bloomberg.net.

Last Updated: September 29, 2005 23:16 EDT