Last week, we focused on the on-farm threats posed by New World Screwworm and the small wounds that can serve as entry points for the fly. But the effort to keep the pest out of U.S. herds goes far beyond the pasture. There is an even bigger challenge tied to the movement of livestock and wildlife, and the work being done behind the scenes to keep the fly from moving north. Those efforts are less visible than border announcements, but they remain a central part of the prevention strategy.
Elanco’s Dr Wayne Ayers says that animal movement itself is one of the biggest risks. Cattle that cross the border or move between regions can carry pests with them if health checks and protocols are not followed. Wildlife creates its own threat, since deer, wild hogs, and other species do not recognize fences, borders, or inspection stations.
Dr Ayers says border restrictions and livestock inspections are not always popular, and they do create economic challenges. But those measures exist to prevent the fly from taking hold in U.S. herds. The same is true for cattle movement protocols on both sides of the border. Even though many producers are following the rules, it only takes a few exceptions to create a new outbreak.
That prevention approach is not new. It is the same strategy that was used sterile male flies to push the pest out of the United States decades ago and eventually drive it deep into Central America. That program remains the foundation of the long-term plan. The sterile male system works because the female screwworm fly only mates once. If she mates with a sterile male, her eggs become infertile. That single step stops the next generation before it ever begins.
Dr Ayers says the cooperation between Mexico and the United States continues to expand that program. New facilities are being built to produce sterile male flies and supply the eradication effort. The goal is simple. Keep the fly from moving north and protect livestock before an infestation ever begins.
More information on the sterile male program, border work, and screwworm prevention is available through the USDA New World Screwworm playbook.
