The virus that causes severe acute respiratory syndrome (SARS) in humans can also infect domestic cats and ferrets, researchers have discovered. The study suggests that the virus may have a wide variety of natural hosts instead of just one, the researchers say; it's also showing the way to new animal models for SARS.
SARS is widely assumed to have originated in an animal, but researchers still don't know which species. In a study first released in May and published in Science this month (10 October, p. 276), researchers reported isolating a virus from Himalayan palm civets in southern China that matched SARS almost exactly. Other evidence implied that two other species--raccoon dogs and Chinese ferret badgers--had been infected too. And another team discovered that cats had become infected in Amoy Gardens, a Hong Kong apartment complex that was heavily hit by SARS.
Following up, Albert Osterhaus and his colleagues at Erasmus University in Rotterdam, the Netherlands, inoculated six ferrets and six domestic cats in their tracheas with a SARS coronavirus strain derived from a deceased Hong Kong patient. Three of the six ferrets got sick, and one died; the cats appeared to remain healthy. But pharynx swabs showed that all of the animals shed the virus 2 days after inoculation, Osterhaus reports in the 30 October issue of Nature. They spread the disease too: When noninoculated cats or ferrets were put together in a cage with infected ones, they, too, became infected.
The fact that two such distantly related carnivores are both susceptible suggests that the SARS virus is "quite promiscuous," says Osterhaus. That means researchers hunting for the natural reservoir may have to cast a very wide net. For SARS researchers, the study has an added bonus: Ferrets, already in use as model animals for influenza, may be a good species to test candidate drugs and vaccines, he says, in addition to monkeys and mice (ScienceNOW, 7 October 2003).