New World Screwworm Threatens South Texas Livestock

The New World Screwworm (NWS), a parasitic fly known for consuming the flesh of livestock and other warm-blooded animals, has been detected in South Texas. The United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) confirmed the presence of NWS larvae found in a calf in Zavala County on June 3. By June 11, six cases had been reported by federal officials.

According to the USDA, the NWS is a severe pest impacting livestock, pets, wildlife, and less frequently, humans and birds. These larvae, or maggots, penetrate the flesh of living animals, causing significant harm and economic losses, although they do not render meat unsafe for consumption. However, there is concern that NWS could cause beef prices to rise further, which are already at high levels.

USDA Secretary Brooke Rollins announced on May 11, 2025, that imports of live cattle, horses, and bison through U.S. ports along the southern border were suspended due to NWS’s rapid expansion in Mexico. Dudley Hoskins, USDA Under Secretary for Marketing and Regulatory Programs, acknowledged the time bought by efforts across the Trump administration and related partners.

“USDA invested heavily in the tools needed to eliminate NWS ever since cases started increasing in Central America and Mexico,” Hoskins stated. “The United States has defeated this pest before, and we will do it again.”

An APHIS strike team is quickly responding by releasing sterile male flies and implementing a movement control zone in Texas to quarantine livestock.

In the 1920s and 1930s, USDA efforts initiated NWS eradication. The Screwworm Adult Suppression System (SWASS), which uses insecticide-laced bait, was a key solution. Eradication was declared in 1966.

Texas Agriculture Commissioner Sid Miller has criticized the USDA’s current strategy. “For months, the screwworm has advanced rapidly through Mexico despite the USDA’s existing plan,” Miller remarked, noting the lack of complete strategy implementation despite billions of sterile flies being dispersed.

Miller urged President Trump to expedite the response, suggesting immediate usage of SWASS and full federal engagement to avert a potential agricultural crisis. The Texas Land Commission, directed by Dawn Buckingham, M.D., has offered resources to bolster governmental efforts by providing access to land for operations such as fly cultivation and trap setup.

Buckingham highlighted the broad risk posed by NWS to both livestock and wildlife. “We want to be sure that we get these insects out of our state,” she expressed.

With increased global movement, screwworms can spread rapidly, infiltrating areas through various means. Buckingham emphasized their experience and available treatments, confident they will manage the situation effectively.

Teresa Mull is part of the Fox News Digital Lifestyle team as a freelance writer.