Key facts
- Smuggled horses crossing the U.S.-Mexico border are raising concerns about the spread of New World screwworm.
- The flesh-eating parasite has already infested U.S. cattle since June, despite efforts to contain it.
- Illicit animal trafficking continues along remote border stretches, bypassing required veterinary inspections and health certifications.
- A widespread screwworm outbreak could cost the U.S. economy an estimated $1.8 billion.
- Mexico has confirmed over 2,000 equine screwworm cases in 2024.
- U.S. officials are increasing efforts to crack down on illicit livestock movements.
Smuggled horses crossing the U.S.-Mexico border are raising concerns about the potential spread of New World screwworm, a flesh-eating parasite that has begun infesting U.S. cattle. Despite efforts to contain the pest, including restrictions on cattle imports, illicit animal trafficking continues along remote stretches of the border, bypassing crucial veterinary inspections and health certifications.
In late May, sheriff's deputies intercepted a trailer carrying six horses near Redford, Texas, which had crossed illegally from Mexico. While these horses were not infested, the case highlights a vulnerability in the U.S. response to the screwworm threat. Trafficked animals can move quickly through smuggling networks, potentially accelerating the spread of the fly far beyond its natural capabilities.
Mexico's animal health agency, Senasica, has confirmed over 2,000 equine cases of screwworm since the outbreak began in 2024. Experts estimate that a widespread screwworm outbreak in Texas could cost the economy up to $1.8 billion, a significant concern given a previous outbreak in the 1960s that killed thousands of animals.
Authorities have intercepted over 50 smuggled horses in Presidio County alone in the past two years, with trafficked horses fetching high prices on the black market. The U.S. Department of Agriculture Inspector General has described animal trafficking as a national security issue heightened by the screwworm threat, noting that recent smuggling seems more pronounced. The USDA Secretary of Agriculture has stated the department is cracking down on these illicit movements.
Law enforcement officials are increasingly focusing on horse trailers as a means for smugglers to transport animals, often blending in with rural life. These undocumented crossings evade inspections and pose disease-transmission risks similar to those linked to illegal cattle movements from Central America.