SARS virus can spread in lab animals.

Virologists have found that ferrets and domestic cats can acquire and transmit the virus that causes severe acute respiratory syndrome (SARS). An independent group of researchers has determined that Chinese animal traders--particularly those dealing in wild mammals--have particularly high rates of past exposure to the virus.

Cats that researchers intentionally exposed to the virus didn't become visibly ill, but the virus did replicate in the animals' blood. Ferrets similarly infected did get sick, and one died. Both cats and ferrets housed with infected members of their species also acquired the virus, Albert Osterhaus of Erasmus Medical Center in Rotterdam, the Netherlands, and his colleagues report in the Oct. 30 Nature. Either species could be used to test the effectiveness of future vaccines or drugs, the scientists say.

In a separate study, researchers at the Guangdong Center for Disease Control in Guangzhou, China, tested blood from 792 people in Guangdong Province, where the SARS epidemic began last November. In the Oct. 17 Morbidity and Mortality Weekly Report, the researchers note that 13 percent of animal traders, but only 2.1 percent of medical workers and other volunteers in the study, had evidence in their blood of past exposure to the SARS virus. Exposure rates among animal merchants ranged from 19 percent in those selling cats to 73 percent in traders of masked palm civets. B.H.