There’s troubling news for many of the nearly quarter of a million farms and ranches in Texas. Canada has suspended animal imports from Texas due to the threat of the New World screwworm (NWS).
Those animals include horses, pigs, cattle and other warm blooded animals. As Texas Public Radio reports, the Canadian Food Inspection Agency says livestock that originate from, or were present in the state of Texas within 21 days prior to a border crossing, will not be accepted into Canada.
Canadian officials say while the country's colder climate is not hospitable for the long-term establishment of the parasite, they can survive short periods during the summer months.
The Canadian agency says it will continue to work closely with U.S. counterparts to assess developments and adjust measures as needed. The U.S. Department of Agriculture (USDA) has confirmed a total of 37 cases of the parasite in the U.S. All but one case has been in Texas.”
While fears of NWS have been building for years, As The Texas Tribune reports, official confirmation of the infestation of the flesh-eating flies took place last month in south Texas. A potential cause was identified by the Texas Animal Health Commission as small wildlife and rodents, such as armadillos, opossums, and rabbits.
Yet, according to the Texas Parks and Wildlife Department (TPWD), the source of the first case of NWS to cross the U.S. border remains under investigation. It was 13 months earlier, on May 11, 2025, that the USDA took the major step of closing all southern ports of entry to Mexican livestock, a preventative step still in place today.
To eradicate NWS along the U.S./Mexico border region, a projected 500 million sterile flies are required weekly according to experts. However, presently, a facility in Pacora, Panama and operated through the Panama-United States Commission for the Eradication and Prevention of Screwworm currently produces 100 million sterile flies on a weekly basis.
On May 27, 2025, Agriculture Secretary Brooke Rollins announced that the USDA would be investing $21 million in an 18-month renovation of an existing fruit fly production facility in Metapa, Mexico to produce an additional 100 million sterile NWS flies weekly when it is running at full capacity.
And by June 27, 2026 Rollins attended a ceremony at that same facility for the official opening. U.S. Secretary of State Marco Rubio joined her on the official trip, where Mexican President Claudia Sheinbaum Pardo greeted the U.S. delegation.
But state and federal officials concede reaching the 500 million sterile fly production threshold is not possible yet. Authorities also add that other technologies discussed recently are also not ready for deployment, either. Those technologies include:
- NovoFly: A developing male-only genetic NWS strain currently under review by the EPA.
- eBeam Sterilization: Advanced electron beam systems are being integrated to sterilize fly pupae.
- Modular Dispersal Units: Rapid-deployment, modular sterile-fly units are being utilized to bridge production gaps while major domestic breeding facilities are constructed.
- SWASS (Screwworm Adult Suppression System): A proposed method that combines sterile flies with targeted, over-the-counter fly attractant baits designed to eliminate 85% to 95% of the wild population prior to sterile fly release.
- Detection & Trapping Systems: Modern biocontrol relies on high-tech surveillance, including Internet-of-Things (IoT) smart-trap systems and the deployment of specially trained sniffer dogs to
- rapidly track and intercept insects.
