CHICAGO, Sept 29 (Reuters) – The U.S. government said on Friday that a decision by France to vaccinate ducks against avian flu will trigger restrictions on imports of French poultry beginning Oct. 1.

France will start requiring vaccinations of ducks in October, making it the world’s first country to launch a nationwide vaccination campaign, according to French farm ministry officials.

The United States does not allow poultry imports from countries affected by highly pathogenic avian influenza (HPAI) or from flocks vaccinated against the disease, known as bird flu, the U.S. Department of Agriculture said.

Vaccinated birds may not show signs of infection, the USDA said, meaning it is impossible to determine whether the virus is in a flock.

“France’s decision to vaccinate presents a risk of introducing HPAI into the United States,” the USDA said.

“Vaccination of poultry against HPAI virus may mask HPAI virus circulating in poultry.”

France’s embassy in Washington could not immediately be reached for comment.

France has been among the countries worst affected by an unprecedented global spread of bird flu that has killed hundreds of millions of birds in the past two years, disrupting supply of poultry meat and eggs and spurring import bans.

The U.S. has suffered its worst outbreak, in which nearly 59 million chickens, turkeys and other birds died since 2022. U.S. officials tested vaccines but have not approved their use.

Trade restrictions threaten U.S. imports of day-old chicks and hatching eggs from France for the breeding industry, said John Clifford, veterinary trade policy advisor for the USA Poultry and Egg Export Council, an industry group.

“It’s got some impact,” he said.

Clifford said the U.S. wants information about how France will monitor vaccinated flocks for signs of disease.

The U.S. will also restrict imports of live ducks, duck eggs, and untreated duck products from other European countries, including those in a zone known as the European Poultry Trade Region, the USDA said.

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