USDA Won’t Restrict Cattle Imports From Mexico Over Latest Screwworm Case

Livestock in pens before being exported to the United States, at the Chihuahua Regional Livestock Union facility, outside Ciudad Juárez, Mexico, on February 10, 2025. Jose Luis Gonzalez/Reuters

The U.S. Department of Agriculture (USDA) will not impose restrictions on cattle imports from Mexico after the discovery of another case of New World screwworm (NWS) in a cow south of the border, the agency said on Feb. 18.

The department announced in November 2024 that it was temporarily blocking shipments of Mexican cattle and bison into the United States to protect livestock and other animals after NWS was detected in a cow at a checkpoint near Mexico’s border with Guatemala.

At the time, the USDA said it was working with Mexico to implement measures to resume the normal flow of Mexican exports. The temporary pause on shipments led to U.S. cattle supplies tightening for some months until February, when the restrictions were ultimately lifted.

The USDA said on Feb. 1 that it would lift the November ban following “extensive discussions between representatives from the countries” and the implementation of a “comprehensive pre-clearance inspection and treatment protocol to ensure safe movement and mitigate the threat of NWS.”

Another case of screwworm was found in a cow in the Mexican state of Tabasco last week, according to the World Organization for Animal Health.

Despite the latest detection, the USDA said on Feb. 18 that it will not be taking additional action.

The discovery in Tabasco pushed up feeder cattle futures at the Chicago Mercantile Exchange amid anticipation that the USDA might pause imports from Mexico again.

“The comprehensive pre-clearance inspection and treatment protocol is now in place and will ensure safe movement of cattle and bison into the United States and mitigate the threat of New World screwworm,” the USDA said in response to questions from Reuters.

The Epoch Times has contacted the USDA for further comment.

What Is New World Screwworm?

According to the USDA, the New World screwworm, also known as Cochliomyia hominivorax, or simply screwworm, is a devastating parasitic pest that can infest livestock, wildlife, and in rare cases, people.

Maggots (or larvae) from screwworm flies burrow deep into the skin of living animals in a screwing motion using their sharp mouth hooks, hence the name.

The more maggots that hatch and feed on the living tissue, the larger the wound becomes. As a result, NWS can cause serious, often fatal damage to the animal.

Signs and symptoms of infestations include irritated behavior, head shaking, and the smell of decay, according to the USDA.

While NWS is endemic in Cuba, Haiti, the Dominican Republic, and countries in South America, cases have spread north to Costa Rica, Nicaragua, Honduras, Guatemala, and now Mexico in recent years.

This is in part due to new areas of farming opening up in previous barrier regions for fly control as well as increased cattle movements into the region, according to the USDA.

While NWS was eradicated from the United States in 1966 using a sterile insect technique, there is a “constant risk of re-introduction” into the United States, according to the department.

The USDA’s decision not to place restrictions on cattle imports from Mexico comes as U.S. cattle supplies have plunged to their lowest levels in 74 years, while beef prices have soared, partly because ranchers were forced to cull their herds after widespread drought reduced the amount of land available for grazing.

Higher interest rates and escalating loan expenses have further burdened cattle farmers, prompting many to liquidate their herds or quit the business altogether.

Kevin Stocklin and Reuters contributed to this report.