U.S. Temporarily Suspends Live Animal Imports Due to Screwworm Outbreak in Mexico

In response to the emergence of a serious screwworm outbreak in Mexico, the United States Department of Agriculture (USDA) has implemented a temporary ban on importing live cattle, horses, and bison from Mexico. This decisive measure aims to prevent the spread of the New World screwworm, a flesh-eating parasite that poses significant threats to both animals and humans.

The screwworm was recently detected on farms in Mexican states such as Oaxaca and Veracruz, which are approximately 700 miles from the U.S. border. The parasite's larvae can infect wounds in warm-blooded animals, burrowing into flesh and causing painful infections that can sometimes lead to death. Although primarily an issue for livestock, the screwworm can also infest humans, with Mexico reporting its first human case in April, involving a 77-year-old woman who was successfully treated and remains stable.

USDA Secretary Brooke Rollins emphasized that the move is rooted in concerns over animal and food safety, highlighting that the ban is set to last at least two weeks with the possibility of extension and regular review. This action is not politically motivated but is essential for safeguarding the nation's food supply and agricultural health.

Mexico’s officials, including Agriculture Secretary Julio Berdegué and President Claudia Sheinbaum, have expressed disagreement with the suspension, arguing that Mexico has been actively working to contain the outbreak since its detection. The recent border shutdown follows a similar restriction put into place in November 2024, which lasted until early 2025 when inspection measures were improved.

Historically, screwworms have affected U.S. livestock as well, with outbreaks recorded in the past, such as the 1972 Texas epidemic and a more recent incident in the Florida Keys in 2016. Although the U.S. eradicated the parasite in 1966, recent movements of the pest from Central America into Mexico have prompted renewed concern.

The USDA continues collaborative efforts with Mexico to control and eradicate the screwworm, acknowledging the ongoing threat of northern spread. The agency states that additional measures are necessary to slow the northward progression of this harmful parasite. More information on screwworms and ongoing eradication efforts can be found through the National Invasive Species Information Center.