The U.S. Department of Agriculture (USDA) has announced a new initiative to combat the spread of the New World Screwworm, a flesh-eating fly that poses significant health risks to cattle and humans. The program involves breeding and releasing millions of sterilized male flies over Mexico and Texas to reduce the population of the pest. These flies are rendered infertile through radiation and will be released via airplanes to mate with wild females. The eggs laid by the females will not be fertilized, leading to a gradual decline in the fly population.
In response to the threat, the USDA has implemented measures to restrict livestock imports from the southern border. This was announced by USDA Secretary Brooke Rollins, who cited the risk of the Screwworm as the reason for the shutdown. The agency is also planning to establish a new fly factory in southern Mexico by July 2026 and a distribution center in Texas to manage the release of sterile flies. The strategy builds on past efforts, including the release of over 94 billion sterile flies between 1962 and 1975, which contributed to the eradication of the pest in the U.S.
The New World Screwworm is endemic to several regions including Cuba, Haiti, the Dominican Republic, and parts of South America. These flies are often found in wooded areas but are attracted to livestock such as cattle and horses. A female fly typically lays eggs in open wounds or orifices of warm-blooded animals, where the eggs hatch into larvae that burrow into the flesh, causing severe damage. The USDA has emphasized the importance of controlling the spread of the pest to prevent potential health risks to both animals and humans.
The USDA’s efforts to combat the Screwworm are part of a broader strategy to protect agricultural interests and public health. The agency’s Animal and Plant Health Inspection Service (APHIS) has provided critical information on the biology and behavior of the pest, highlighting its potential to cause significant harm if left unchecked. Despite the challenges, the USDA is confident that the sterile fly program will contribute to the long-term management of the Screwworm, reducing the impact on livestock and minimizing health risks.