The USDA Animal and Plant Health Inspection Service (APHIS) published an updated New World Screwworm (NWS) response playbook on April 8, 2026. The document is a step-by-step guide for coordinated action if the pest is ever detected inside the United States. Federal, state, tribal, and local responders are all addressed in the playbook.
The New World Screwworm is a parasitic fly whose larvae burrow into the open wounds of living warm-blooded animals. It can affect livestock, pets, wildlife, and in rare cases people. The pest was eradicated from the United States in 1966 but has been moving northward through Central America and Mexico in recent years. The updated New World Screwworm response playbook reflects the urgency of that threat.
What does the New World Screwworm response playbook cover?
The playbook outlines science-based strategies across several critical areas. These include how to coordinate response operations, reduce the spread of NWS, manage the pest in infested animals, conduct surveillance of screwworm flies, and maintain continuity of business during an outbreak. Furthermore, it provides guidance on how to keep information flowing efficiently across all agencies and partners involved in a response.
USDA Under Secretary for Marketing and Regulatory Programs Dudley Hoskins emphasized the importance of readiness. He noted that while the agency works aggressively with Mexico to prevent further northward spread, domestic response plans must also be ready for immediate activation. He added that strong coordination with producers, veterinarians, sportsmen, and other partners is essential.
The updated New World Screwworm response playbook also adds and refines guidance on wildlife management. This includes clearer definitions of confined, farmed, and free-ranging wildlife, along with improved guidance on use of antiparasitic drugs and pesticides in wildlife settings. Ranchers and veterinarians looking for more detail on treatment options can also visit Agroinformacion’s coverage of FDA emergency drug options for NWS.
How was the playbook developed and updated?
APHIS first shared a draft of the playbook in October 2025. In the months that followed, the agency gathered feedback from state animal health officials, federal partners, livestock and wildlife industry groups, tribal partners, and veterinary organizations. That input shaped the final version released in April 2026.
Key updates include clearer terminology around NWS establishment, suspect cases, quarantine zones, and outbreak phases. Agency roles, responsibilities, and legal authorities are also now more clearly defined. Animal movement requirements have been updated as well, reflecting lessons learned from preparedness exercises and partner consultation.
In addition to the main playbook, APHIS updated four existing supplemental guidance documents and added eight new ones. All twelve are referenced directly within the playbook to give responders a complete, field-ready resource for real-world scenarios.
What steps is USDA taking beyond the playbook?
The playbook is one part of USDA Secretary Rollins’ five-pronged plan to keep NWS out of the United States. In March 2026, the USDA and the U.S. Army Corps of Engineers signed a contract to build a new sterile fly production facility in Texas. Meanwhile, the FDA issued an Emergency Use Authorization for a topical spray to prevent and treat NWS infestations in cattle, sheep, goats, horses, and other animals.
APHIS has also set up more than 8,000 traps across Texas, Arizona, and New Mexico to monitor for screwworm flies. The agency says it will continue revising the playbook as preparedness activities advance. Moreover, APHIS will keep working directly with states, territories, tribes, and federal partners to refine response tools and strengthen joint planning. The APHIS New World Screwworm information page provides current updates on the ongoing response.
The updated New World Screwworm response playbook was published by the USDA Animal and Plant Health Inspection Service on April 8, 2026, on the APHIS official news page.