The creep of New World screwworm just outside U.S. borders has livestock producers on high alert. The fly, whose larvae burrow into the flesh of living animals, causes serious and often fatal damage. Cattle are among the most vulnerable animals, making the pest a major threat to the beef and dairy industries in particular.
Though the pest was eradicated from the U.S. in the 1960s and ’70s and a small outbreak was quashed in 2017, its recent spread north through Central America and Mexico has sparked fresh concerns of another outbreak. There are currently no confirmed cases in the U.S., but a recent confirmed case in Coahuila, Mexico, just 119 miles from the Texas border, has officials on edge.
In a statement, Texas Agriculture Commissioner Sid Miller said the “threat is advancing fast, and every Texan needs to take notice.”
Federal agencies continue to move quickly to enforce preventive measures. In May 2025, the USDA halted imports of live cattle, horse, and bison imports into the U.S. from Mexico.
Just last month, Florida Commissioner of Agriculture Wilton Simpson took even more aggressive action to protect our state by placing temporary restrictions on the importation of animals into Florida from high-risk counties in Texas, including Zapata, Jim Hogg, Starr, Hidalgo, Webb County, and Brooks counties.
In late April, the FDA issued an Emergency Use Authorization for Negasunt Powder, a topical treatment that combines coumaphos, propoxur, and sulfanilamide to treat and prevent NWS.
A widespread outbreak could be devastating for the U.S. beef industry. According to the USDA, NWS threatens over $100 billion in United States economic activity tied to the cattle and livestock industry alone. In addition, industry experts warn that increased NWS activity could drive beef prices higher.