(NDAgConnection.com) – A near-record number of U.S. chickens and turkeys have died in this year’s outbreak of avian flu, as a different form of the virus than farmers battled before has infected more wild birds that then transmit the disease, officials said.

According to Reuters, more than 47 million birds have died due to infections and cullings. This has spurred export bans, lowered egg and turkey production, and contributed to record prices of the staples ahead of the U.S. holiday season. The outbreak exacerbates economic pain for consumers grappling with soaring inflation.

In 2015, 50.5 million birds died in the deadliest U.S. outbreak, the nation’s worst animal-health event to date.

Farmers are fighting a subtype of the H5N1 strain of the virus that survived over the summer, when rising temperatures typically reduce avian flu, said Rosemary Sifford, chief veterinary officer for the U.S. Department of Agriculture (USDA).

The same subtype, known as the goose/Guangdong lineage, is spreading in Europe, she said in an interview. Europe is already suffering its worst avian flu crisis, with nearly 50 million poultry culled.