for National Geographic News
After a new case of Severe Acute Respiratory Disease, SARS, was confirmed in China earlier this week, officials there ordered the widespread culling of civets, weasel-like mammals that have been linked to the transmission of the virus.
But are these animals the real culprits or are they just becoming scapegoats for a more complex, man-made problem?
While some health officials warn the slaughter of civets could destroy important clues about how the virus is transmitted, some wildlife conservationists charge that eliminating whole species may actually destroy natural buffers to the spread of viruses between animals and humans.
They warn that infectious and previously unknown diseases will continue to proliferate as human populations expand and venture further into wild habitats. Instead of vilifying wildlife and eliminating species, the conservationists say, the focus should be on preventing transmissions.
"It is becoming clear that the majority of emerging infectious diseases can be attributed to human activities that impact natural ecosystems," said Jonathan Epstein, a veterinarian and wildlife epidemiologist at the Wildlife Trusts Consortium for Conservation Medicine in Palisades, New York. "There are so many potentially dangerous pathogens in wildlife that we don't yet know about, and we need to consider this whenever we expand human settlement into pristine habitat, or move wildlife around the world as part of our global trade."
Identifying the Reservoir
SARS, a form of atypical pneumonia, first broke out in Guangdong province in southern China in November 2002. It infected more than 8,000 people and killed 774 around the world before it was brought under control in June last year.
Almost three weeks ago, a 32-year-old freelance television producer was hospitalized in Guangdong with an ailment that was later confirmed to be SARS. Health officials described his case as mild. On Thursday, he was released from hospital.
But on Thursday, the Chinese news agency Xinhua reported a second suspected case of SARS: a waitress in China's southern city of Guangzhou.
When SARS first broke out, scientists quickly identified it as a coronavirus and said it was probably transmitted to humans by an animal. In May last year, researchers from the University of Hong Kong examined 25 animals from eight species in a live animal market in southern China, and found a SARS-like virus in all six civet cats they sampled, as well as in a badger and a raccoon dog.
But a study by scientists from the China Agricultural University later failed to find evidence to link the civet cats to the disease. The World Health Organization maintains that no definite link has been established, and the TV producer who fell ill with SARS is not believed to have been exposed to civets or any other wild animals.
"We think civet cats are involved in the transmission of SARS, but we can't say if the virus jumps from civets to humans or if another animal is involved," Klaus Stöhr, who coordinated WHO's SARS program and now heads the WHO global influenza program, said in a telephone interview from Geneva, Switzerland.
SOURCES AND RELATED WEB SITES