The microbiology team from the University of Hong Kong has published a paper on the origins of the coronavirus that causes severe acute respiratory syndrome (SARS). The paper, published online in Science (www.sciencemag.org/cgi/content/abstract/1087139) on 5 September, presents the results of testing eight species of wild and domestic animals sourced from a live animal market in Shenzhen, southern China, in May 2003. The paper also showed that eight traders of wild animals and three workers who slaughtered wild animals were positive for the virus, despite never having shown symptoms of SARS.
A total of 25 animals were tested, and researchers isolated a SARS-like coronavirus from four civet cats, as well as from a raccoon dog. Antibodies were also found in three palm civets, a raccoon dog, and a Chinese ferret badger.
The genetic sequences of the human SARS coronavirus and the virus detected in the civet cat and other animals were very closely related, according to Dr Guan Yi, associate professor at the University of Hong Kong's faculty of medicine. "The virus detected in animals was a little different to the human one, so we called it a SARS-like virus," he said.
The team also took blood samples from 1500 workers and for the research paper published results of testing on 55 workers. Of these, eight wild animal traders, three workers who slaughtered wild animals, and one vegetable seller were seropositive for the SZ16 coronavirus, but none of them had reported SARS-like symptoms in the previous six months. "We don't know why the workers didn't show symptoms. They could have been infected, several years, even a decade ago," said Professor Yuen Kwok-yung, head of the University of Hong Kong's department of microbiology.
The research represents an important advance but leaves many questions unanswered, such as whether the trading and consumption of wild animals should be banned, said Professor Yuen. "We need to look at what control measures are the most reasonable, ranging from intense surveillance of how animals are caught, transported, killed, and cooked, to a complete ban of wild animal markets. More research needs to be done to assess the risk," he said.
The research has also not identified the natural reservoir of the virus, a task that will take years not months, said Dr Henk Bekedam, China's representative for the World Health Organization. "Now we have a clear indication that the virus and antibodies have been found in civet cats, but that's not the same as saying we've found the reservoir or that the virus has jumped from this animal to humans," he said.
WHO, in collaboration with the United Nations' Food and Agriculture Organization, has recently presented its findings to the Chinese authorities on what further steps need to be taken in determining the origin of SARS.
"What our team has said to the Chinese government is that broad research is needed, and early on we strongly advised the Chinese government to seek international collaboration. We are very hopeful, but it is still a major challenge to ensure things get started with the cooperation of the central government, the provinces, and the international community," said Dr Bekedam.
· Singapore based biotechnology company Genelabs Diagnostics, in partnership with the Institute of Molecular and Cell Biology, unveiled on 5 September a kit that can test for SARS in 15 minutes, says a report from Agence France-Press. The kit is currently undergoing field tests, and the company expects it to be available for sale within the next two months.