Virus claim disputes the popular theory
A US study on the evolution of Sars has challenged a popular hypothesis established by Hong Kong and mainland scientists that the deadly virus was passed to humans by civet cats.
The severe acute respiratory syndrome corona-like virus found by researchers in palm civets kept in restaurant cages in Guangdong was actually passed from humans to the animals, not the other way around, an Ohio State University research team said.
But leading scientists in Hong Kong and the mainland said there was no new evidence to back up the team's contention.
The theory, posted online in the early edition of the research journal Cladistics, says only a small number of people who were in daily contact with civets were infected because the animal was not an amplifying source of the virus but an inheritor.
It has been half a decade since the global outbreak of the epidemic, but the original carrier of the virus - although almost certainly a mammal - had not yet been identified, the researchers said.
If the theory is accurate, the culling of nearly 10,000 civet cats by Guangdong authorities in 2004 may have been in vain and the widespread belief that Sars was eradicated that year because of the campaign against the animals could be dangerously wrong.