that broilers are sent to slaughter at an optimal age for viral shedding, as well as from the large numbers of broilers that traveled to that facility. Millions of birds shedding viruses traveling in trucks to Turlock easily spread the infection to farms along the route. That is when the Turlock region, which is bound by three major highways, became known as the Triangle of Doom: a bird couldn’t enter the area without becoming infected with H6N2. An estimated 35 million birds in California became infected with this H6N2 virus during a 4-month period beginning in March 2002.

Perhaps more astonishing than the extent and speed of this outbreak was the fact that no one outside the region heard much about it. The virus was not a feared H5 or H7 subtype, but the Triangle of Doom was also kept quiet by corporate decision-makers who feared that consumer demand would plummet if the public knew they were buying infected meat and eggs, safe though they may be to eat. Thus, other than the initial diagnosis of the broiler flock, all other diagnoses were made by corporate veterinarians, and the results were not released—not to the state or to other potentially affected states, not to the Office International des Épizooties, not even to neighboring farmers, who might have better protected their flocks from infection had they known about it. H6N2 has since become endemic in California, following its spread to farms that raise birds for the state’s live fowl markets.

Eventually, the poultry producers in the Triangle of Doom developed a biosecurity plan to curtail the spread of the virus, and thereby restore egg and poultry production. The plan does not penalize farms that test positive for influenza, and it provides for the safe movement of eggs and broilers to market from infected facilities. These sorts of protections need to be offered to the industries that raise much of the poultry (and swine) in the United States in order to achieve complete surveillance and their cooperation in addressing avian influenza. Similar dense poultry and swine populations exist throughout the country. Any one of them could be the site of the next outbreak of an emergent influenza virus.

SOURCE: Cardona (2004).

Since the height of the Asian avian influenza in February 2004, the FAO has recommended vaccination against influenza “where appropriate and practical,” but the practice remains prohibited in several Asian nations (ProMED-mail, 2004r). Japan and Korea, the only Asian countries that successfully controlled and eradicated H5N1 following the recent epidemic, did so through culling alone. Thailand is currently considering the possibility of immunization following a resurgence of H5N1 in July 2004, although as a major poultry exporter, it will surely take into consideration the European Union’s ban on poultry imports from countries where chickens have been vaccinated against avian influenza. Vaccination against avian influenza is not widely practiced in the United States due to its high cost relative



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