On Dec. 13, 2024, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) announced $165 million in emergency funding from the Commodity Credit Corporation to protect U.S. livestock and other animals from New World screwworm (NWS) and to increase USDA’s ongoing efforts to control the spread of NWS in Mexico and Central America. NWS are fly larvae that infest living tissue of warm-blooded animals, causing infection.

Over the last two years, NWS has spread throughout Panama and into Costa Rica, Nicaragua, Honduras, and Guatemala. The funding bolsters USDA’s work in Mexico and Central America to stop the spread of NWS from moving north in Mexico, further protecting the United States through surveillance, animal health checkpoints and domestic preparedness, and by working with partners in Mexico and Central America to establish a barrier on the Isthmus of Tehuantepec, eradicate NWS from the affected areas, and reestablish the biological barrier in Panama.

Eradicating NWS is only possible through sterile insect technique. With this method, sterile flies are released into an area where a known population has become established. The sterile male screwworm fly mates with fertile female screwworm fly, causing the population of screwworm flies to decrease until it eventually dies out.