The current outbreak of highly-pathogenic avian influenza in British Columbia, Canada, and the Pacific Northwest of the United States is associated with wild bird migration in the Pacific flyway, said Dr. Fidelis Hegngi, senior staff veterinarian, U.S. Department of Agriculture Animal and Plant Health Inspection Service. He told the audience of the United Egg Producers’ Board meeting in Atlanta, Georgia, that the first case of avian influenza found in wild birds in Washington State, on December 8, 2014, was genetically identical to the H5N2 avian influenza virus found earlier in British Columbia, Canada. He said that the H5 was of Eurasian lineage and the N2 was North American lineage, which indicated that there has been re-assortment of the viruses from the two continents.
Hegngi said that an avian influenza virus found on December 16, 2014, in Washington State was an H5N8 of Eurasian lineage. Subsequently, avian influenza was found in wild birds, backyard chicken flocks and guinea fowls, and in captive raptors in the states of Washington, Oregon and Idaho.
On January 23, an H5N8 avian influenza outbreak was confirmed on a Foster Farms turkey ranch in California. This is the first instance of the virus being found in a commercial flock in the U.S. in this outbreak. Hegngi said that this strain is particularly pathogenic for turkeys and that the mortality was extremely high in the first house that broke with the virus. The ranch is a large one, and it housed nearly 145,000 hens and toms at the time of the outbreak. All of the birds either died from the disease or were euthanized. Hegngi said that Foster will be indemnified for the value of the birds.
Hegngi implored egg producers to be vigilant and “follow strict biosecurity practices and raise your birds in very controlled environments.” He said, “What should an egg producer be doing? Biosecurity, biosecurity, biosecurity."
Mass euthanasia on egg farms is still a challenge, Hegngi reported. He said that foaming techniques developed for use on floor housed broilers and turkeys hasn’t really worked well for caged layers, but that a system in development at Mississippi State University using compressed air foaming on cages which have a manure belt under them to hold the foam has shown promise. He said that this system will likely need to use carbon dioxide in the gas mix to ensure humane euthanasia.