The Journal of Infection has now posted this article as uncorrected proof: Illicit poultry selling was probably the source of infection of the first H5N1 case in the Americas imported from Beijing. Never mind the Chinese authors' awkward English; the editors will clean that up, but the content is clear. Read the whole thing. The conclusion:
Since 2005, the slaughtering and selling of live poultry have been prohibited in the markets of Beijing, and the citizen can only get access to the processed poultry after quarantine from legal channels of circulation.
However, in some places in Beijing, especially in suburban and rural areas, some dealers still sell live poultry transported from the regions outside of Beijing at their home-based stall or in flea markets, with the information of quarantine unclear, and this kind of selling mode appears very hard to be tracked and managed.
Besides the H5N1 case in 2009 contracting H5N1 virus from the asymptomatic duck from Hebei, four H7N9 cases detected in Beijing including two symptomatic cases and two asymptomatic cases were also infected by exposure to live poultry from the regions outside of Beijing. Among these four H7N9 cases, three came from the families of chicken dealer in suburban areas of Beijing who ever purchased asymptomatic chickens infected with H7N9 virus from Tianjin and sold them to the citizens in Beijing.
Although the Beijing government makes efforts to ban the illegal deal of live poultry, this selling mode consistently exist as many Chinese people prefer live poultry to fresh poultry in light of their culture of consumption.
With regard to the source of infection for the first H5N1 case in the Americas imported from Beijing, it could not be excluded that this case contracted the virus when passing some inconspicuous stalls or dealers in flea markets sneaking off to sell live poultry as the case had no obvious history of contacting live poultry and no H5N1 virus was found in our recent surveillance toward poultry raised in Beijing (960 environmental samples from November to December, 2013) and wild birds (3322 feces samples from November to December, 2013).
The above-mentioned evidences indicate that illegal and uninspected selling and transportation of live poultry from regions outside of Beijing may have posed a high risk on human infection with avian influenza in the general population of Beijing currently.
The enhanced inspection on illegal selling of live poultry, the strict regulation of transporting live poultry from regions outside of Beijing, as well as the health education on changing dietetic culture is greatly warranted in Beijing, in order to reduce the risk of infection with avian influenza viruses in the general population of Beijing including visiting foreigners.
Ever since the first outbreak of H5N1 in Hong Kong in 1997, the message has been clear: People trying to make a living by selling poultry are inadvertently killing some of their customers. That poses an enormous political problem for governments—not just in Asia, but around the world.