With US Cattle at Risk, Texas Breaks Out the Flies

The first center for dispersing sterile screwworm flies from US soil in decades opened Monday in Texas, part of a larger effort to keep the flesh-eating parasite they spawn from crossing the Mexican border and wreaking havoc on the American cattle industry. US Agriculture Secretary Brooke Rollins and Texas Gov. Greg Abbott unveiled the new facility on a former Air Force base near Edinburg, Texas, reports the AP. The move will allow the US to disperse millions of sterile male New World screwworm flies bred in Mexico or Panama on both sides of the border.

The USDA is building a new $750 million factory nearby for breeding sterile flies, but Rollins said construction on the fly factory won't be done until the end of 2027. The agency also is spending $21 million to convert a fruit fly breeding facility in far southern Mexico into one for breeding screwworm flies starting this summer. The sterile male flies would mate with wild females, who mate only once in their weekslong adult lives. Their eggs, laid in open wounds or on mucous membranes, would then not hatch into the flesh-eating maggots that can infest livestock, wild mammals, household pets, and even humans.

"It's a real testament to the all hands on deck ... that we do not have the pest in our country yet," Rollins said. In November, the USDA opened a facility in Mexico's Tampico for dispersing Panama-bred flies. However, it's about 330 miles south of the US-Mexico border. "We knew we needed a short-term, gap-filling solution, which is exactly what we are cutting a ribbon on today," Abbott said. The Mexican cattle industry has been hit hard by New World screwworm fly larvae infestations, and the US has closed the border since July to imports of cattle, bison, and horses.

A similar program breeding sterile male flies had largely eradicated the pest from American soil by the early 1970s, except for a limited, short-lived outbreak in the Florida Keys in 2017 and its appearance recently when officials blocked a horse being imported from Argentina into Florida until the animal was fully treated, Rollins said. The US shut down its fly factories after eliminating the pest from its soil, and sterile males have been bred since in the Western Hemisphere only at a single facility in Panama, which can produce about 117 million a week. The new fly factory in Texas would be designed to produce 300 million a week.