insisted on stricter practices to protect their operations. In Europe, which was experiencing a similar chicken boom, many farmers had turned to banks for financing and inked contracts with feed mills. Both demanded measures to safeguard their investments.
Asia, for the most part, has yet to follow suit. So today, birds in China and Southeast Asia are amassed in once unimaginable densities, often weakened by their stressful confinement and exposed to the whims and wrath of viruses like influenza. The tremendous amounts of feed, water, and human traffic required to maintain these flocks offer a generous avenue to infection. In the unnatural setting of intensive agriculture, chickens are more vulnerable to contagion because they are pressed together and housed atop one another’s droppings, which are a main way, if not
It’s not only the
But researchers have also found there’s something even more perilous than a country of dense commercial chicken farms. That’s one like Thailand, a country in transition, where commercial farms operate in the midst of extensive traditional flocks. These small holdings represent a vital link in the chain of infection. For the flu virus to migrate from its natural reservoir in waterfowl, it needs an initial toehold in domestic poultry. Asia’s traditional backyard farms, with their freely grazing birds and even fewer safeguards, offer just this opening. They are like kindling wood around the larger commercial farms. And the larger commercial farms, which have mostly sprung up near their markets, are concentrated around another vulnerable population: the unprecedented accumulation of humanity in the metropolises of East Asia.
As Jan Slingenbergh of the UN Food and Agriculture Organization and his fellow researchers write, “Agricultural practices have become the dominant factor determining the conditions in which zoonotic pathogens evolve, spread and eventually enter the human population.” More pointedly, the FAO said in 2008 that the rapid development of Asia’s poultry industry without due regard for animal health created a “virtual time bomb” that “exploded” with the outbreak of H5N1.
Sangwan Klinhom was a Thai country singer in the parts around Suphan Buri. His resonant tenor earned him a following, but little money. The tips couldn’t even pay the rent. “If you’re a singer, you’re very poor,” he explained. “Some die without a coffin.” So he eventually abandoned the circuit of farmyard weddings and cheap beer joints for the roving life of a duck herder.
When I encountered him in the shade of a coconut tree, Sangwan was rolling a homemade cigarette fashioned from a palm frond. He would occasionally glance up to check on his flock, nearly a thousand khaki Campbell ducks pecking and scavenging in the mucky waters of a rice paddy several miles north of Banglane village. Despite the intense midday heat, he wore a heavy brown knit cap with a blue pompom to keep the sun off his head. His brow was deeply furrowed, his jowls weathered. Beneath thick, graying eyebrows, his deep-set eyes were bloodshot from sun and stress. Once again, he was singing a plaintive tune.
The practice of grazing ducks in rice fields, which initially developed in southern China, had long since spread to the wetlands of Southeast Asia. Herders like Sangwan followed the rice harvest, trucking their flocks from province to province in pickups and feeding the ducks for free on residual grains, insects, and snails in the muddy water. “The ducks give you anything you want,” he told me. “If you want something, you wait a bit and you get it. I didn’t even have a house before.” But now this barefoot nomad and countless others like him were being pressed by Thai officials to renounce their wandering ways and shut their flocks up in closed shelters. Ducks had been fingered as silent killers.
Researchers had discovered that ducks were spreading the novel flu strain like never before while no longer displaying any symptoms of their own. Wild waterfowl had long been recognized as a natural host for flu viruses, carrying the infection without getting sick. As the pathogen grew more virulent, it initially turned on the cousins of these wild birds, domesticated ducks, and caused widespread die-offs. For a while, this helped tip public health officials to proliferating poultry outbreaks that could endanger people. But in 2004, the virus abruptly changed its modus operandi a second time. Infected ducks once again showed no symptoms, according to an international team of scientists based at St. Jude Children’s Research Hospital in Memphis. But now these infected birds spread the virus in larger amounts and for longer periods, in some cases a week longer than before. The virus also survived for more time in the surrounding water than it ever had. The duck had become “the Trojan horse” for Asian flu viruses, the researchers warned darkly.
When investigators in Thailand tested flocks of free-range ducks, nearly half proved to be infected with flu despite few signs of illness. Scientists warned that traditional duck farming posed a tremendous risk not only in Thailand’s central plains but also in the Mekong River delta of southern Vietnam and the Red River delta of northern Vietnam.
Separate studies of the bird flu epidemic in Thai poultry had also deeply implicated free-ranging ducks. The research showed that outbreaks in the chicken population were concentrated in areas where ducks commonly graze, primarily wetland areas of intensive rice cultivation. Suphan Buri was singled out as a hot spot for disease. By contrast, provinces with high concentrations of chickens but few ducks largely escaped the brunt of the epidemic. The authors suggested that paddies were a likely meeting point where migratory water birds relayed contagion to ducks, which in turn infected chickens before shuttling it to other fields and provinces.
Sangwan said his rambling took him through the rice paddies of more than ten provinces over the course of a season. Every two or three days he moved on, generally drifting southward with the harvest. Only hours earlier, after exhausting the pickings in a nearby field, he had herded his flock to a new paddy, where young rice plants were just starting to poke through the still surface. “I marched them here like little soldiers. ‘Keep walking,’ I told them. ‘Keep walking.’ ” He gestured with his open palms to show how he nudged them along, a smile settling on his stubbly face and crow’s-feet deepening at the corners of his eyes. The ducks had filed down the grassy banks into the water, waddling and ruffling their tail feathers. A flotilla set sail with a whoosh toward a low line of palms on the distant shore. Sangwan had claimed a rare sliver of shade on the dike. He lay down his long bamboo rod and stretched out his scrawny legs.
At the end of the day, Sangwan and his wife would line the birds up again and march them back to the campsite. The ducks spent their nights in a temporary enclosure of plastic sheeting. Sangwan looked for a dry patch of earth to pitch his tent. “I’ve gotten used to living in the open fields,” he said. “I love spending the time with the ducks rather than in a house, where you have to hear a television and people talking and traffic on the street.” In the hours before dawn, he would listen to his charges rustle as they scouted for comfortable nooks to lay their eggs. “That’s a nice sound,” he mused. “That’s the sound of making money.”
Sangwan had turned to herding two decades earlier as the livestock revolution was accelerating, doubling and redoubling Thailand’s duck production. As a younger man, he had dabbled in construction, growing rice, and raising vegetables. He took up singing after winning a local contest. Later, dead broke, he persuaded his uncle to teach him about ducks. He learned how to call to them in an authoritative voice so they’d respect and obey him. But alone on the dikes, Sangwan still serenaded his flocks with ballads of rural heartbreak.
Lowering his cigarette to his side, his melancholy voice began to carry across the glistening paddies, rising above the soft swooshing sound of birds foraging in the water.
He returned the cigarette to his lips and took a long drag. His sunken cheeks slipped even deeper into shadow. Then he continued.
