Canada has suspended several animal exports from Texas due to concerns about the New World screwworm, according to the U.S. Department of Agriculture.
The Canadian Food Inspection Agency is immediately suspending the export of horses, pigs, cattle, bison, sheep, goats, deer, elk, moose, llamas and more. Imports from other states are permitted, provided the animals have not resided in or passed through Texas during the 21 days immediately prior to their arrival in Canada.
The USDA stated in a news release on Tuesday that its accredited veterinarians must include information on whether the animal resided in or was transported through a state affected by New World Screwworm, and that exporters/shippers have been advised that this is required; otherwise, the shipment will be refused entry into Canada.
The Canadian Food Inspection Agency announced in a news release that it will continue to work closely with its United States counterparts to assess developments and adjust measures as needed.
“While our colder climate is not hospitable for the long-term establishment of the fly in Canada, they can survive shorter periods of time in the summer months,” the CFIA stated in the news release. “Taking this action now is an appropriate risk mitigation measure to prevent its introduction and protect animal health.”
The decision comes after an infestation of flesh-eating flies was confirmed in South Texas in June, setting off alarm bells for the state’s cattle industry.
Since then, the New World screwworm has continued to infiltrate livestock and other animals in Texas, with 34 confirmed cases as of July 10.
The Texas Animal Health Commission identified a potential cause last month: small wildlife and rodents, such as armadillos, opossums, and rabbits.
Until then, USDA Secretary Brooke Rollins has pointed to multiple causes, including border policies under President Joe Biden and the illicit movement of cattle at the hands of drug cartels.
However, the source of the first case of New World Screwworm remains under investigation, according to the Texas Parks and Wildlife Department. Other health experts say it’s still undetermined what allowed the invasive pest to finally breach the Texas-Mexico border.
The USDA closed all southern ports of entry to livestock imports from Mexico in May 2025 and has kept them closed since then, preventing cattle from legally crossing into the U.S. from Mexico.
Experts project that 500 million sterile flies are needed weekly to eradicate the pest, and at the moment, the U.S. government is producing about 100 million every seven days out of a facility in Panama.
That capacity is set to expand, but not enough to reach the 500 million threshold. And other technologies officials hope to pair with fly sterilization are not yet ready for deployment or are the subject of disagreement, leaving the Trump administration and Texas officials without a speedy path to eradicate the threat.
Disclosure: Texas Parks And Wildlife Department has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in The Texas Tribune’s journalism. Find a complete list of them here.
by Stephen Simpson, The Texas Tribune
July 14, 2026