Long’s case is part of an ominous outbreak that began in China and could, according to experts in Asia and the United States, evolve into a pandemic. H7N9 first spread from birds to humans in 2013. Since then, there have been five waves of the virus. The fifth wave began in October 2016. By September 2017, it had infected 764 people—far more than any of the four preceding waves. Health officials recently confirmed that there have been 1,589 total cases of H7N9, with 616 of them fatal. “Anytime you have a virus with a 40 percent mortality rate,” says Tim Uyeki, the chief medical officer for the influenza division at the U.S. Centers for Disease Control and Prevention, “that’s very, very serious.”
So far, the only verified means by which patients have acquired the virus is through direct exposure to infected animals. But if H7N9 were to mutate further and develop the ability to pass readily from person to person, it could spread rapidly and kill millions of people worldwide. The potential for disaster has normally cautious medical researchers expressing concern, even suggesting that H7N9 might rival the fierce influenza virus that caused the 1918 pandemic, which killed between 50 million and 100 million people.
Guan Yi, a virus expert and noted flu hunter at the University of Hong Kong School of Public Health, has predicted that H7N9 “could be the biggest threat to public health in 100 years.” Specialists at the Centers for Disease Control and Prevention warned this past June that out of all the novel influenza strains they’d recently evaluated, H7N9 has the highest potential “to emerge as a pandemic virus and cause substantial human illness.”
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Officially, the live-bird markets in Beijing have been shuttered for years. In reality, guerrilla vendors run furtive slaughterhouses throughout this national capital of wide avenues, gleaming architecture and more than 20 million residents—despite warnings that their businesses could be spreading deadly new strains of the flu.
In one such market, a man in sweatstained shorts had stacked dozens of cages—jammed with chickens, pigeons, quail—on the pavement outside his grim hovel.
I picked out two plump brown chickens. He slit their throats, tossed the flapping birds into a greasy four-foot-tall ceramic pot, and waited for the blood-spurting commotion to die down. A few minutes later he dunked the chickens in boiling water. To de-feather them, he turned to a sort of ramshackle washing machine with its rotating drum studded with rubber protuberances. Soon, feathers and sludge splashed onto a pavement slick with who knows what.
I asked the vendor to discard the feet. This made him wary. Chicken feet are a Chinese delicacy and few locals would refuse them. “Don’t take my picture, don’t use my name,” he said, well aware that he was breaking the law. “There was another place selling live chickens over there, but he had to shut down two days ago.”
Many Chinese people, even city dwellers, insist that freshly slaughtered poultry is tastier and more healthful than refrigerated or frozen meat. This is one of the major reasons China has been such a hot spot for new influenza viruses: Nowhere else on earth do so many people have such close contact with so many birds.
At least two flu pandemics in the past century—in 1957 and 1968—originated in the Middle Kingdom and were triggered by avian viruses that evolved to become easily transmissible between humans. Although health authorities have increasingly tried to ban the practice, millions of live birds are still kept, sold and slaughtered in crowded markets each year. In a study published in January, researchers in China concluded that these markets were a “main source of H7N9 transmission by way of human-poultry contact and avian-related environmental exposures.”
In Chongzhou, a city near the Sichuan provincial capital of Chengdu, the New Era Poultry Market was reportedly closed for two months at the end of last year. “Neighborhood public security authorities put up posters explaining why bird flu is a threat, and asking residents to co-operate and not to sell poultry secretly,” said a Chongzhou teacher, who asked to be identified only as David. “People pretty much listened and obeyed, because everyone’s worried about their own health.”
When I visited New Era Poultry in late June, it was back in business. Above the live-poultry section hung a massive red banner: “Designated Slaughter Zone.” One vendor said he sold some 200 live birds daily. “Would you like me to kill one for you, so you can have a fresh meal?” he asked.
Half a dozen forlorn ducks, legs tied, lay on a tiled and blood-spattered floor, alongside dozens of caged chickens. Stalls overflowed with graphic evidence of the morning’s brisk trade: boiled bird carcasses, bloodied cleavers, clumps of feathers, poultry organs. Open vats bubbled with a dark oleaginous resin used to remove feathers. Poultry cages were draped with the pelts of freshly skinned rabbits. (“Rabbit meat wholesale,” a sign said.)
These areas—often poorly ventilated, with multiple species jammed together—create ideal conditions for spreading disease through shared water utensils or airborne droplets of blood and other secretions. “That provides opportunities for viruses to spread in closely packed quarters, allowing ‘amplification’ of the viruses,” says Benjamin John Cowling, a specialist in medical statistics at the University of Hong Kong School of Public Health. “The risk to humans becomes so much higher.”
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Flu viruses can mutate anywhere. In 2015, an H5N2 flu strain broke out in the United States and spread throughout the country, requiring the slaughter of 48 million poultry. But China is uniquely positioned to create a novel flu virus that kills people. On Chinese farms, people, poultry and other livestock often live in close proximity. Pigs can be infected by both bird flu and human flu viruses, becoming potent “mixing vessels” that allow genetic material from each to combine and possibly form new and deadly strains. The public’s taste for freshly killed meat, and the conditions at live markets, create ample opportunity for humans to come in contact with these new mutations. In an effort to contain these infections and keep the poultry industry alive, Chinese officials have developed flu vaccines specifically for birds. The program first rolled out on a large scale in 2005 and has gotten mixed reviews ever since. Birds often spread new viruses without showing signs of illness themselves, and as Guan notes, “You can’t vaccinate every chicken in every area where bird flu is likely to emerge.” In July, after H7N9 was found to be lethal to chickens, Chinese authorities rolled out H7N9 poultry vaccines; it’s still too early to assess their impact.
Is China Ground Zero for a Future Pandemic? Nov. 2017, Smithsonian