The United States has once again closed its southern border to imports of livestock due to concerns about a dangerous parasite spreading in Mexico. This parasite, known as the New World screwworm fly, poses a serious risk to the beef industry. The U.S. officials are particularly worried about its economic impact if it reaches Texas.
The female screwworm fly lays eggs in wounds on warm-blooded animals. This leads to larvae that feed on living flesh, which is notably harmful compared to other insects that usually feed on dead matter. U.S. officials remember the significant economic losses caused by this pest in the past and want to be cautious.
In response to the discovery of the fly in southern Mexico late last year, the U.S. had previously closed its border to live cattle, horses, and bison. Although there was a plan announced to reopen several ports of entry, recent reports indicate that the infestation is now closer to the Texas border than previously thought.
Agriculture Secretary Brooke Rollins emphasized the need for vigilance and quick action to tackle this issue. He credited the ongoing monitoring efforts by USDA staff for keeping the situation under control.
On the other side, Mexican President Claudia Sheinbaum criticized the U.S. decision, arguing that it was an overreaction. Her government is actively managing the situation and claims that the number of infected animals in Mexico has decreased.
Meanwhile, the U.S. is planning to invest nearly $30 million in strategies to combat the screwworm, including breeding sterile male flies to reduce the population. A new fly factory is expected to be operational in southern Mexico by July 2026. Additionally, there are plans to establish a site in southern Texas for holding sterile flies, ready for release if the situation worsens.
U.S. lawmakers, including representatives from Texas and Florida, are advocating for the swift approval of existing treatments to help manage the screwworm population among livestock, signaling that they want to address the threat head-on.
