Agriculture officials ordered the culling of 73,500 chickens on a Tennessee farm near the border with Alabama, and put 30 nearby poultry farms under quarantine following discovery of highly pathogenic avian influenza in the breeding flock. It was the first case of “high path” bird flu in commercial poultry in the nation this year.
The USDA confirmed that the H7 virus was involved; testing should soon identify the neuraminidase protein, or N-type. Health official are worried especially about the H7N9 strain, which is involved in an ongoing outbreak in China and which has jumped species to infect and kill humans. The WHO says at least 460 Chinese have been infected since last October and a third of them died, reports the Washington Post.
Some 50 million turkeys and egg-laying hens died during the worst-ever U.S. outbreak of bird flu over six months from late 2014 through spring 2015. Ten percent of the U.S. laying flock was lost, driving up egg prices for months to follow. Migratory wild fowl were “the original pathway” for the disease to attack flocks, but humans had a hand in spreading it from farm to farm, the USDA said in a June 2015 analysis. It recommended more stringent procedures to prevent contamination and to separate domestic flocks from wild fowl.
“Many Tennessee families rely on the poultry industry for their livelihoods, and the state is working closely with local, county and federal partners and the poultry industry to control the situation and protect the flocks that are critical to our state’s economy,” said Gov. Bill Haslam in a statement.
Officials were monitoring flocks within 6 miles of the infected farm in Lincoln County. “No other flocks have experienced an increase in mortality,” said the Tennessee Agriculture Department. The state said it was the first time that high-path bird flu was found in Tennessee.
The Tennessee farm is a broiler breeder operation, meaning it produces eggs that are hatched to produce broiler chickens for meat.
Risk of human infection by the disease is low, said Tennessee officials, who added that no farmworkers contracted influenza during the 2014-15 epidemic, which was centered in the Midwest.
The National Chicken Council, a trade group, encouraged poultry farmers to maintain heightened biosecurity protocols. The group said it would work with USDA to minimize any disruption to U.S. exports. Dozens of nations restricted export of U.S. broiler meat during the 2014-15 epidemic.
The last U.S. outbreak of “high path” bird flu, which gets its name for its high mortality rate, was on a turkey farm in southwestern Indiana. Authorities ordered the extermination of 401,163 turkeys and egg-laying hens on the farm, and nine nearby farms, to prevent spread of the virus. Depopulation, as the USDA and the poultry industry term the process of killing an entire flock, is the primary method to prevent the spread of bird flu, following quarantine of an infected flock and restriction on movement of poultry on neighboring operations while checking them for disease.
To read a Feb. 28 Ag Insider story about the bird flu situation in China and around the world, click here.
The CDC page on H7N9 avian influenza is available here.