TEXAS, USA — A tiny maggot from Central and South America, notorious for its destructive impact on livestock, is advancing swiftly northward, causing concern among Texas authorities.

The invasive larva, known as the New World screwworm, was recently detected in González, Tamaulipas, approximately 215 miles from the Texas border, reported Commissioner Sid Miller. This marks the third instance of a screwworm infestation in Tamaulipas.

Editor’s note: The above video was initially broadcast on December 12.

This pest derives its name from its harmful behavior of burrowing into open wounds on both livestock and humans, as explained by Texas A&M AgriLife Research. Without timely detection and treatment, the infestation can cause severe harm and potentially lead to death.

The increased risk from screwworms to wildlife and livestock in Texas and throughout the United States has driven renewed attention to the parasite, which was previously eradicated from the nation in the 1960s. Before that, the screwworm devastated livestock across the Southern U.S., Mexico, Central and South America, according to the American Society for Microbiology. 

In the most recent case in Tamaulipas, the infected animal had no reported history of movement outside the area, signaling that the pest might be moving closer to Texas on its own, without links to commercial animal movement.

“Texas producers must act now — stay informed, stay vigilant, and prepare immediately. We cannot drop our guard for even a moment,” Miller said. “Inspect your animals daily. Check every open wound. If anything looks suspicious, report it right away. Better a false alarm than a delayed response — early detection and rapid reporting are our strongest defenses against this devastating pest.”

Miller said the state’s agriculture department is working closely with the U.S. Department of Agriculture, which is collaborating with Mexico’s National Service for Health, Safety, and Agro-Food Quality to investigate the cases further and stop the pest’s spread.

The first human case of screwworm was identified in August after a Maryland resident traveled to El Salvador and returned home. The person recovered, and investigators did not find the infection transmitted to any other people or animals.

U.S. agriculture officials halted live cattle crossing the border in July – the third suspension of the eight months — due to concerns about the flesh-eating maggot, the Associated Press reported. All southern ports of entry remained closed to livestock trade since the July suspension.