TOLEDO, Ohio (AP) — An outbreak of bird flu that has led to the deaths of 43 million chickens and turkeys this year across the U.S. has been found at a giant egg-laying operation in Ohio, state and federal agriculture officials said Wednesday.

The case confirmed over the weekend in Ohio's Defiance County has affected roughly 3 million chickens, according to the U.S. Department of Agriculture. The egg-laying farm has started euthanizing all of its flock, said Dennis Summers, the state’s veterinarian.

The highly pathogenic disease has returned to the Midwest earlier than authorities expected after a lull of several months with cases in Indiana, Minnesota, North Dakota and Wisconsin within the past week. There also have been several detections in western states over the summer.

The disease is typically carried by migrating waterfowl, such as geese and ducks, Summers said. It only occasionally affects humans, such as farm workers, and the USDA keeps poultry from infected flocks out of the food supply.

The outbreak that earlier this year contributed to a spike in egg and meat prices appeared to be waning in June, but officials warned then that another surge could come back this fall.

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