Unhealthy mix of animals, humans
By CNN's Marianne Bray
HONG KONG, China (CNN) -- In a bustling market in the southern Chinese province of Guangdong, dogs, cats, chickens, frogs, snakes, turtles and palm civets are stacked on top of each other in crates, wire cages and water buckets ready for sale.
Customers peer at the caged animals before choosing their meal of the day. They watch as the butcher cuts up the animal with knives and machetes, spreading blood, guts, faeces and urine all over the market floor.
People from South China believe that eating wild animals is good for their health and vitality, and gulping down such exotic fare as cobra and Asiatic brush tailed porcupine is seen as a symbol of social status.
Indeed, there is a saying in South China that "anything with four legs, except a chair, and anything that flies, except an aeroplane, can be eaten."
One especially famous dish is the "Dragon-Tiger-Phoenix Soup," a brew made up of snake, cat and chicken.
South China offers the most exotic fare from all over the globe -- by some accounts at least 60 species can be found in any one market --thrusting together microorganisms, animals and humans who normally would never meet.
This thriving trade gives the manufacturing hub that straddles the Pearl River Delta the unenviable title of being the "petri dish" of the world.
"Animals arrive at these markets stressed, diseased, dying and dead," Animals Asia, a Hong Kong-based charity dedicated to ending cruelty for animals in the region, says on its Web site.
"These animals have no free access to food and water or shelter from the elements and are mixed indiscriminately."
It was from just such a market in a village near the provincial capital of Guangzhou that researchers believe the deadly SARS virus originated in 2003, with civet cats high on the list of suspects.
The respiratory disease, which killed 774 people and sickened 8,098 in 30 nations, sparked panic in nearby Hong Kong, with most of its 7 million residents donning masks in a bid not to be infected when someone coughed or sneezed.
Public campaigns warned Hong Kongers to wave good-bye instead of shaking hands and to avoid touching elevator buttons and escalator handrails.
But SARS was not an isolated outbreak.
South China has long been the epicenter of pandemic flus, giving birth to three or four global outbreaks a century.
The Asian flu of 1957 and the Hong Kong flu of 1968 are both believed to have originated in southern China, while the Russian flu of 1977, which appeared in the city of Anshan, was widely thought to be a re-emergence of the 1957 flu.
And some experts, including Kennedy Shortridge, who worked in Hong Kong for many years and teaches at New Zealand's Auckland University, believe the Spanish flu of 1918 spread along the Chinese coast and was carried to America by Chinese immigrants.
That flu alone killed one in 60 of the world's people at the time.
All these flu pandemics can be traced to viruses caught from birds. Virologists believe the flu jumped species when ducks were domesticated in South China 3,000 years ago.
With their weak immune systems, ducks become flu incubators, with the virus then jumping to pigs and mutating to a form people can catch.
Living cheek to jowl
While live animal markets can be found all over Asia, South China is unique because so many people live so close together, with a very traditional way of life abutting a glittering modern China.
Guangdong province has become China's most populous area, with migrants swelling the population to 110 million people. Across the province, for every square kilometer there are 618 people living on top of each other in towering blocks.
In Guangzhou, the New Baiyun International Airport handles nearly 500 flights a day, serviced by multi-lane highways and 5-star hotels that have sprouted in empty fields, making it a flu heartland.
Outside the city limits, farmers eat, sleep and work in teeming and cramped quarters with ducks, chickens and pigs in traditional and often squalid conditions, creating a toxic brew that can easily spread to the modern China, and to the rest of the world.
This is also a place where dietary staples and traditional Chinese medicine like turtle shell are in hot demand. Early on, a lack of regulations, record-keeping and research between Hong Kong and China, and a suppression of information by Beijing, stunted any efforts to clamp down on outbreaks.
But in many ways, SARS was a wake-up call to China, scaring authorities into action.
After seeing the rapid toll SARS took on the economy and public sentiment in 2003, health experts told a conference in Bangkok last year that China is now getting serious about stopping the spread of AIDS.
Last year China began offering voluntary testing and counseling and free medication for the poor.
China says around 840,000 people are infected with HIV/AIDS, but the United Nations has said the number could be higher.
As Chinese authorities begin realizing the importance of preventing flu epidemics and other diseases, health experts say they face difficult challenges.
The number of animals held in captivity is rising as is the transport of animals, all of which allows viruses to make the jump with more opportunity, Malik Peiris, a professor of microbiology at the University of Hong Kong, told CNN.
China's millions of migrant workers, who make a beeline for the prosperous south and are difficult to keep track of, could further spread viruses.
Experts say China needs to monitor what is happening on the ground and learn more about the ecology of animals that are farmed to avoid future pandemics.
"By doing surveillance we know what is circulating, we know what is out there, and which are most serious contenders," says Peiris.
"One can narrow potential culprits and be prepared with vaccines."