In 1998, 30% of the markets were infected with H7N2, particularly in the New York metropolitan area. New York has more live markets than all other states in the Northeast combined. By 2001, inspectors could find the virus at 60% of markets at any one time.
The states were failing to control the problem. With the virus dangerously close to potentially locking in that final mutation, the USDA had to intercede, coordinating a system-wide closure of all retail live poultry markets throughout the northeastern United States in 2002. Following the mass closure, all birds were sold off or killed, and all markets were cleaned and disinfected, left empty for days, and then repopulated with birds only from closely monitored source flocks confirmed to be negative for all avian influenza viruses. Then they watched and waited. Within five weeks, H7N2 was back.
It is unknown whether the virus somehow persisted in the markets or was reintroduced. Regardless, despite their best efforts at eradication and control, it seems clear that live poultry markets represent a public health risk. Writing in the Journal of Virology, USDA researchers concluded that "the rampant reassortment of AIVs [avian influenza viruses] in the LBMs [live bird markets] could increase the risk of species crossover because it would increase the chances of the occurrence of the correct constellation of genes to create a virus that replicates efficiently in mammals."
The mass market closure and disinfection did seem to knock the virus back a step, though, back to three basic amino acids. Still, unless all live poultry markets are closed, H7N2 will presumably continue its march towards virulence. As the director of the virology lab at Cornell University's Animal Health Diagnostic Center put it, "It is two major mutations away from becoming a virus that could kill a lot of chickens and become much more pathogenic to people." Currently, many suspect that H5Nl is going to beat H7N2 to the pandemic punch, but were it not for H5Nl, the betting might be on live poultry markets in New York City-not Hong Kong-to deliver the next killer superflu virus. According to the USDA's Agricultural Research Service:
"The U.S. currently has the largest, most genetically homogeneous and, thus potentially, the most disease-susceptible population of food animals in the history of mankind .... The emergence of a new disease or a slight shift in the epidemiology of an existing disease could lead to immediate and disastrous results for American livestock producers and consumers."
The Virginia outbreak in 2002 that led to the deaths of millions of birds and found its way onto hundreds of farms highlights just how wishful the thinking is that industrial poultry populations are protected by biosecurity. Based on the rapid spread of bird flu in United States in 2002, leading USDA poultry researchers have concluded the obvious: "[B]iosecurity on many farms is inadequate." The situation has not necessarily improved since then, according to the executive editor of Poultry magazine and professor of poultry science at Mississippi State. In 2005, she editorialized, "I believe it is time to reexamine biosecurity in our industry. We've become lax in many ways, and this is exactly what it took to get the 1983 AI outbreak moving." She continued, "If WHO is right and a pandemic brings human AI to the United States, will you be able to look your family and neighbors in the eye and say you've done all you can to stop the spread? Having to answer that question alarms me!"
Michael Greger "Bird Flu: A Virus of Our Own Hatching" (2006)
