Texas governor slammed Ottawa’s move as an “overreaction” despite declaring a statewide disaster
Canada has temporarily banned imports of livestock, including horses, from the US state of Texas over the outbreak of screwworm fly, a flesh-eating and potentially deadly parasite.
The first case of screwworm was identified in Texas on Wednesday, marking the first detection of the parasite in the US, roughly 80km (50 miles) from the Mexican border. The outbreak began in Central America in 2023 and has been spreading steadily northward ever since. By late 2025, Mexico had reported thousands of cases in animals and dozens of humans.
The second case was identified on Friday in the same area, prompting Texas officials to declare a state of disaster over the outbreak. The same day, the Canadian Food Inspection Agency said it would temporarily halt imports of livestock from Texas until further notice and “continue to work closely with US counterparts to assess developments and adjust measures as needed.”
The ban applies to all livestock that originated from or were present in Texas during the three weeks prior to entering Canada.
Texas Governor Greg Abbott has condemned Ottawa’s move as an “overreaction” despite branding the outbreak an “imminent threat” as he declared a state of disaster.
“This pest affects live animals and does not impact inspected Texas beef. Canada’s broad restriction on Texas livestock is an overreaction that is more political than science-based,” the governor told USA Today in a statement.
The parasite, which in its adult form resembles a common housefly, lays its eggs into wounds and natural body openings of warm-blooded animals. The eggs – laid in hundreds by a single fly – hatch into parasitic maggots, which feast for about a week on living flesh, causing an extremely painful and potentially deadly condition. The maggots ultimately burrow out of the bodies of their hosts and dig into soil to pupate, emerging as an adult fly several weeks later to repeat the process.
The screwworm was declared eradicated in the US in 1966, in Mexico in 1991, and all across Central America by the mid-2000s. The program involved mass-breeding and release of sterile male flies into nature to destroy the population of the parasite. The resurgence of the fly in recent years has been attributed to changing weather and warmer temperatures, which are thought to drastically increase the range of the insects.
