South Texas ranchers brace as flesh-eating screwworm advances toward border, threatening cattle herds

A confirmed case of the New World Screwworm less than 70 miles from the US-Mexico border could further drive up the cost of beef in the Rio Grande Valley, where the weekend barbecue is a common staple.

The U. S. Department of Agriculture said the screwworm was detected along a major highway that runs from Laredo to Monterrey near Sabinas Hidalgo, a city in the Mexican state of Nuevo Leon. The parasitic fly attacks cattle by entering through a wound and laying eggs. 

Despite the proximity of the flesh-eating pest, Isaac Sulemana, chief of staff for Hidalgo County Judge Richard F. Cortez, said there is no objective data that shows the screwworm has arrived in the Valley.

“It moved 300 miles, undetected,” Sulemana said, noting it was found in July about 370 miles south of the border. “We have a robust surveillance system, and there is no confirmation of screwworm in our area.”