WASHINGTON, D.C.--Scientists have reported three new animal models that could provide relatively cheap and practical ways to test drugs and vaccines against severe acute respiratory syndrome (SARS), the disease that erupted from southern China last spring.
These are the not the first animal models for SARS; that honor goes to a monkey. During the peak of the SARS crisis last April, virologist Ab Osterhaus and colleagues at Erasmus University in Rotterdam, the Netherlands, inoculated cynomolgus macaques with a newly discovered coronavirus. The monkeys developed a pulmonary infection resembling SARS in humans, providing proof that the new virus was indeed the culprit, as well as the first animal model. In Rotterdam and elsewhere, researchers are now studying SARS pathogenesis and testing candidate drugs in infected monkeys.
But using monkeys poses ethical questions; besides, they're cumbersome and expensive animals to experiment with, especially under strict biocontainment standards. At a meeting here last week, organized by the Institute of Medicine's Board on Global Health, Kanta Subbarao of the National Institute of Allergy and Infectious Diseases said she had sprayed the SARS virus into the noses of mice and found that, although the animals didn't get sick, the virus started replicating inside their bodies--sufficient for an animal model. "Everybody is calling us to test their pet vaccine," says Subbarao, who has submitted the results for publication.
In a paper that has been accepted by Nature, meanwhile, Osterhaus reports that his group has infected two other species with SARS and found that the virus readily replicates in both. Osterhaus declined to reveal the two species pending publication, but he says they are more closely related to masked palm civets and ferret badgers--two species in which the SARS virus has been found in China (ScienceNOW, 23 May)--than they are to mice. The findings suggest that the virus may have a remarkably broad range of hosts, Osterhaus says.
Subbarao's announcement was one of the few tangible steps forward reported during last week's meeting. With drug and vaccine studies in their infancy and the flu and cold season about to hit the Northern Hemisphere, many questioned whether overstretched public health systems will be able to cope if SARS reemerges. Summarizing his feelings after the meeting, National Center for Infectious Diseases director James Hughes said, "What I've heard doesn't make me sleep any better."