A team of international scientists has reinforced theories that Severe Acute Respiratory Syndrome originated in southern China. Other experts are considering a new theory that rats could have spread SARS in a Hong Kong apartment building.
As they wrapped up their tour of southern China Tuesday, the experts said there is evidence that the SARS virus came from wild animals in the region.
Scientists from the World Health Organization, the United Nations Food and Agricultural Organization, and the Chinese government spent 12 days hunting for clues about SARS' origins in China's Guangdong Province.
"The epidemiological evidence in that Guangdong area where we first had the appearance in the human population because that evidence is suggesting it was contacts with markets that was [a] risk factor, then we'll certainly be looking at species that occur in the markets," explained Hume Field, a veterinary epidemiologist with the U.N. team. "Equally important is the need to identify species where there is no evidence of infection. There's no evidence that livestock species have played a role in SARS at all."
In other words, the virus does not appear to have come from cows, pigs, or poultry. Some flu viruses have originated in poultry in the past, and jumped to humans. Dr. Field says the virus may have jumped from any number of animals including civets, badgers and raccoon dogs - all wild mammals eaten in southern China. But Dr. Field says it is too early to determine if the virus originated in any one of these species.
Chinese state media reported the team inspected one of Guangdong's largest farms that breeds civets for eating.
Also this week, an international team evaluating the Hong Kong government's response to SARS says it would consider new research indicating that rats spread the virus in a high-rise apartment complex. Three hundred people in the complex caught SARS.
Earlier researchers concluded that the apartment's design contributed the spread.
Hong Kong was one of the worst hit cities during the global SARS outbreak earlier this year, with about 1,700 cases. Nearly 300 Hong Kong patients died. China recorded more than 5,300 cases and about 350 deaths. SARS spread to more than 30 countries in just five months but Hong Kong and China accounted for more than 80 percent of the world's cases.