An experimental treatment has reduced the severity of SARS in infected monkeys, according to the Maryland-based biotech company Intradigm Corp.
The treatment prevents SARS from infecting cells, and perhaps also from spreading, Intradigm researchers reported in the September issue of the journal Nature Medicine.
The first case of SARS appeared in November 2002. It infected more than 8,000 people around the world and killed about 800, including 44 in Canada and 350 in China. They died of pneumonia and lung failure, caused by the virus. The major symptoms included a very high fever, dry cough, and shortness of breath or breathing difficulties.
SARS was contained using quarantine and isolation. But experts fear another outbreak, and researchers have been steadily working towards vaccines to prevent it, and drugs to treat it.
Intradigm Corp., in Rockville, Md., set up business a year ago to start developing experimental treatments using what are known as "small interfering RNAs," or siRNAs.
These are short stretches of RNA - the genetic counterpart of DNA that actually functions in cells - specifically designed to interfere with certain genes.
Intradigm developed two siRNAs in an attempt to counteract two key genes in the SARS virus.
Then, working with colleagues in China, they put the siRNAs into the noses of 10 monkeys - some already SARS-infected, and some SARS-free. The researchers then infected the SARS-free monkeys. Another group of monkeys was treated with a placebo siRNA that had no activity against SARS, and other monkeys were untreated.
All the monkeys became sick, but those treated developed lower temperatures than untreated or placebo-treated monkeys. And only 25 per cent had detectable virus in their throats, less than the untreated or placebo-treated monkeys.
After the monkeys were killed and their lungs examined, the treated monkeys had fewer infected lung cells.