The United States is preparing to release billions of sterilised flies from aircraft over Mexico and southern Texas in a bid to eradicate a dangerous flesh-eating parasite that threatens to devastate the country’s cattle industry, according to media reports.
This measure targets the New World screwworm fly — which is a parasite that lays eggs in open wounds or mucous membranes of living warm-blooded animals, which also includes humans.
Once ready, these maggots feed on any living tissue from within, which potentially leads to severe infections or even death if the disease left untreated.
“This is not like most flies that feed on dead flesh. A thousand-pound bovine can be dead from this in two weeks,” said Michael Bailey, president-elect of the American Veterinary Medical Association.
The US Department of Agriculture (USDA) will use a long-established method of pest control by mass-breeding male screwworm flies, sterilising them through radiation, and releasing them to mate with wild females.
The sterile mating process results in no offspring, gradually reducing the population of the parasite.
“It’s an exceptionally good technology,” said Edwin Burgess, an assistant professor at the University of Florida who specialises in parasitic insects. “It has the potential to solve some kind of large problem.”
The approach is seen as more targeted and environmentally sustainable compared to conventional pesticide spraying, the AP reported. The technique has been successfully used in the past to eradicate the pest from countries north of Panama.
For years, sterile screwworm flies bred in a facility in Panama were deployed to keep the parasite at bay. However, the parasite was detected again in southern Mexico in late 2024.
In response, the USDA now plans to establish a new screwworm fly facility in southern Mexico, expected to begin operations by the summer of 2026. In the interim, a fly distribution centre will become operational by the end of 2025, allowing the US to import sterile flies from Panama if needed.
The USDA is expected to invest around $8.5 million to establish the Texas distribution facility and another $21 million to convert an existing sterile fruit fly production centre in southern Mexico into one capable of breeding sterile screwworm flies.
