Huge Sterile Fly Facility Opens in Mexico to Counter New World Screwworm

A massive 22,000-square-foot sterile fly production facility has officially been opened in Metapa, Mexico, marking a “major milestone” in the United States’ fight against New World Screwworm (NWS) parasites, the U.S. Department of Agriculture (USDA) said on June 27.Construction of the facility began just 11 months ago. The site will add 100 million more sterile flies to combat NWS spread once it becomes fully operational, the USDA said in a post on X.“The more sterile flies we produce and deploy, the faster we can suppress and ultimately eradicate this devastating pest,” it said.In May 2025, the USDA announced a $21 million investment in the Metapa facility.NWS flies pose a major threat to livestock. The female flies lay eggs on orifices or wounds of warm-blooded animals. When larvae hatch from the eggs, they burrow deep into wounds and eat the flesh. As more eggs hatch, more larvae feed on the animals, the wound becomes larger, and the creature eventually dies.A single NWS female can lay up to 3,000 eggs in its lifetime. A large swarm of these parasites poses a significant risk to U.S. cattle farmers.To combat these growing swarms, authorities use sterile male flies. When these insects are released into NWS swarms, they mate with wild females, which then lay unfertilized eggs, eventually diminishing swarm size.Agriculture Secretary Brooke Rollins met with Mexican President Claudia Sheinbaum Pardo and other partners in Mexico on Saturday to celebrate the opening of the Metapa facility, the department said in a June 27 X post.Rollins “has led the largest New World screwworm response effort in decades—investing $1.3 billion, expanding the NWS workforce by 1,000 percent, and strengthening international cooperation to protect America’s livestock industry,” the post said. “We’ve beaten New World screwworm before—and together, we’ll do it again.”Since 1966, NWS has been considered eradicated from the United States. However, the parasites spread through Central America in 2023 and entered Mexico in 2024, with analysis models showing that the flies had reached the United States by summer last year.Authorities have deployed additional USDA personnel, shut down ports, and set up insect-trapping and surveillance in Mexico, all of which have given time to prepare for the NWS swarms.US NWS InfectionsIn a June 22 X post, the USDA said it confirmed the 16th case of NWS in animals in the United States. According to the department, Mexico has roughly 1,800 active cases.This month, the Food and Drug Administration authorized an emergency medication to treat NWS infestation in dogs and cats.In a June 11 statement, acting FDA Commissioner Kyle Diamantas said the agency has spent almost a year preparing for the NWS arrival.“As of today, under the Trump administration’s decisive leadership, the FDA has issued ten [emergency use authorizations] and three conditional approvals for drugs to combat this threat, and this count will continue to grow as we receive more animal drug submissions and unleash American regulatory speed,” Diamantas said.In its recent X post, the USDA said that the Metapa facility in Mexico was built as part of the department’s “five-point action plan” to counter the NWS threat.The plan, announced in June 2025, includes stopping the parasites from spreading in Mexico, protecting the U.S. border, maximizing readiness, exploring options to eradicate the pests, and pursuing innovative research to improve sterile insect technology.Earlier this month, Rollins announced that President Donald Trump had appointed cattleman and food safety expert John Bellinger as senior adviser on NWS preparedness.“USDA is responding in real time and building up long-term capabilities to push back New World Screwworm beyond our borders,” Bellinger said.“I look forward to working with USDA and our state partners as continuing ramping up testing, detection, and release of our tools to reduce these flies’ populations.”Meanwhile, the Texas A&M University System said in a June 24 post on X that scientists from Texas A&M AgriLife Research are exploring using artificial intelligence to assist in trail-camera monitoring to identify “high-risk locations” where livestock could interact with wildlife.This would help track and forecast where NWS parasites can spread next, the post said.