(NewsNation) — The U.S. Department of Agriculture (USDA) confirmed that highly pathogenic avian influenza (HPAI) was detected in U.S. commercial and backyard poultry flocks this season.

The USDA reported that HPAI, also known as bird flu, was first confirmed in a flock of 47,300 turkeys in Jerauld County, South Dakota, on Oct. 4 and at a farm with 141,800 birds in Utah’s Sanpete County last Friday.

Now, according to the USDA, there are 47 states with at least one confirmed infected flock. HPAI has been confirmed in 329 commercial and 517 backyard flocks, affecting 59.17 million birds.

Infected flocks are culled to prevent the spread of the virus, potentially tightening the poultry meat and egg supply if more cases occur.

“We’re just encouraging bird owners to make sure they’re increasing their biosecurity practices because avian flu is still out there, and it’s easy to contract,” said Bailee Woolstenhulme, spokesperson for the Utah Department of Agriculture and Food.

Before last week, the only reports of bird flu in recent months in the U.S. were sporadic appearances in backyard flocks or among wild birds such as ducks, geese and eagles.

While wild birds often show no symptoms of avian influenza, infections in them are a concern to the poultry industry because migrating birds can spread the disease to vulnerable commercial flocks.

Since 2022, 58.8 million U.S. chickens, turkeys and other birds have been wiped out by the disease, according to the USDA. 

Reuters and the Associated Press contributed to this report.