While this year’s outbreaks of bird flu, the worst in seven years, are following the usual pattern of dissipating during hot weather, it’s too early to declare the threat over, said the Agriculture Department on Wednesday. Forty million birds, mostly chickens and turkeys, have died of the viral disease or during cullings of infected flocks since early February.
The most recent outbreak was in a backyard flock of 30 birds in Yakima, Washington, on June 14. Highly pathogenic avian influenza has been identified only 12 times so far in June, according to a USDA database.
“We hope this outbreak continues the historical trend of waning in summer,” said a USDA spokesman. “We also need to be alert to the virus potentially reappearing in the fall, so poultry producers should remain vigilant, reviewing their biosecurity activities to protect the health of their birds.”
This year’s outbreaks have killed 6 percent of the egg-laying hens in the nation and were blamed for a spike in egg prices around Easter. The nationwide average wholesale price for large eggs was nearly $3 a dozen just before the holiday. It was $1.98 last week, a sharp decline but still far above last June, when wholesale prices dropped to as low as 80 cents a dozen. There have been outbreaks in 36 states this year, with losses highest at egg farms in Iowa and Pennsylvania.
Bird flu, which can be spread by migratory birds, is usually worst during the cold months and fades away with the arrival of warm weather.
The 2014-15 bird flu epidemic killed more than 50 million chickens and turkeys and was “arguably the most significant animal health event in U.S. history,” with an impact in the billions of dollars, said the USDA in a 2016 report.