Canada temporarily blocking livestock from Texas due to New World screwworm

Canada is temporarily restricting the import of livestock from Texas over concerns about a parasitic fly with flesh-eating larvae.

The Canadian Food Inspection Agency said animals that are from Texas or were present in the state within 21 days of a border crossing will not be allowed into the country.

It comes after an infestation of New World screwworm fly larvae was confirmed this week in a calf in Texas. It's the first case confirmed in the state since 1966.

The agency said several U.S. states have also taken precautionary measures to mitigate the risk of spread.

"The CFIA will continue to work closely with U.S. counterparts to assess developments and adjust measures as needed," it said in a news release Friday.

Screwworms can infest livestock, pets, wildlife, birds and even people in rare cases, the agency said. They're not found in Canada and can't survive winter temperatures, preferring hot and humid environments, it said.

U.S. officials have been quick to stress that the fly's larvae — which feed on living material — do not infest meat or fruit.

Officials in Canada are asking animal owners and veterinarians to watch for signs of screwworm infestation in livestock, including wounds that worsen over time and are accompanied by discharge or foul odour.

Canadians travelling to Texas with pets are encouraged to inspect them for any signs of the screwworm.

This report by The Canadian Press was first published June 5, 2026.

— with files from The Associated Press

Copyright 2026, The Canadian Press. All rights reserved.