Key Facts
• In early 2023, screwworm fly larvae outbreak spread across Central America.
• Affected countries include Panama, Costa Rica, Nicaragua, Honduras, Guatemala, Belize, and El Salvador.
• The outbreak reached southern Mexico in November 2023, raising U.S. concerns.
• U.S. Department of Agriculture plans to open a “fly factory” near the Texas-Mexico border.
• Sterile flies will be bred and released via aircraft to control the population.
• Female screwworm flies mate only once in their 20-day lifespan.
• Sterile males can lead to population extinction within months to years.
• A similar method eradicated screwworm flies in the U.S. during the 1960s-70s.
• Current sterile fly production is limited to one facility in Panama.
• U.S. plans include a $21 million renovation of an aging Mexican fly factory by 2025.
Summary
The U.S. Department of Agriculture has announced plans to combat the spread of screwworm flies, a parasitic species threatening livestock. Following a major outbreak across Central America in 2023, the flies reached southern Mexico, prompting concerns about their northward spread. To address this, the U.S. will establish a “fly factory” near the Texas-Mexico border to breed sterile flies, which will be released via aircraft. This method, successfully used in the 1960s-70s, disrupts the reproductive cycle of the flies, potentially eradicating them within months to years. Currently, only one facility in Panama produces sterile flies, necessitating additional resources. The U.S. also plans to invest $21 million to renovate a Mexican fly factory by 2025. Experts assure the public that the flies target rural areas, posing no threat to urban populations.
