The US Department of Agriculture reported outbreaks of a highly lethal type of bird flu in commercial flocks in Maryland and South Dakota over the weekend, adding to concerns that wild birds are spreading the disease across the country.
Farmers are ordered to kill their flocks after the disease is detected, and importing countries including Mexico, China and Korea have imposed state-specific import restrictions in response.
The bird flu outbreak is the worst since 2015, when nearly 50 million birds, mostly turkeys and egg-laying chickens in the US Midwest, were killed. It comes at a time when food prices are skyrocketing due to labor shortages, supply-chain problems and the Russian invasion of Ukraine, a key wheat and corn exporter.
The disease is already widespread in Europe and affecting Africa, Asia and Canada. The United States is the world’s largest producer and second-largest exporter of poultry meat, according to the US government.
USDA reported the H5N1 strain in wild birds in the Carolinas earlier this year. The strain can be passed on to humans, though US officials said there is a low risk to people.
Below are other outbreaks reported by USDA to date.
USDA reported an outbreak of a highly lethal type of bird flu in a commercial flock of chickens being raised for meat in Stoddard County, Missouri, on March 4.
The outbreak was confirmed as the H5N1 strain of avian flu in a flock of about 240,000 broiler chickens in the southeastern Missouri county, the USDA’s Animal and Plant Health Inspection Service said.
Iowa reported a highly lethal form of bird flu in a backyard poultry flock of 42 chickens on March 2, expanding a US outbreak of the disease to the top egg-producing state. In 2015, Iowa was at the center of the biggest-ever US outbreak of avian flu.
A commercial poultry farm with 1.2 million birds was hit by highly lethal bird flu on Feb. 23, significantly expanding the number of birds impacted in the United States.
A flock of about 240,000 chickens owned by Tyson Foods Inc in Kentucky tested positive for a highly lethal form of bird flu, government officials and the company said on Feb. 14.
Testing confirmed a highly lethal form of bird flu in a 53,286-bird commercial turkey flock in Kentucky, the state said on Feb. 16, expanding outbreaks in the US poultry sector.
USDA reported an outbreak of highly pathogenic avian flu in an Indiana turkey flock on Feb. 9. The outbreak infected a flock of 29,015 birds, the nation’s first case in a commercial poultry operation since 2020.
Indiana also reported a case of H5 bird flu at a commercial turkey farm on Feb. 15, impacting a flock of 26,625 turkeys.