The U.S. Department of Agriculture (USDA), in close collaboration with our interagency partners and Mexico’s El Servicio Nacional de Sanidad, Inocuidad y Calidad Agroalimentaria (SENASICA), has made considerable progress in reducing the overall threat of New World screwworm (NWS) to U.S. agriculture and mitigating northern movement of the fly within Mexico. As of November 21, NWS has not been detected in any animals or traps in the United States, and the vast majority of cases within Mexico remain concentrated in southern parts of the country. The Trump Administration remains steadfast in its resolve to safeguard America’s rural economy, domestic food supply, and public health from this invasive pest. USDA is actively investing in physical infrastructure to expand our capacity for sterile fly production and dispersal, while APHIS’ technical experts continue their intensive work across multiple programs and disciplines to further strengthen our strategic planning and domestic preparedness.  

Earlier today, we launched the new unified New World screwworm (NWS) website, screwworm.gov. The new website centralizes NWS information available across the Federal Government and reflects our whole-of-government effort to fight this pest. We invite you to visit this site for the latest USDA-verified information on cases and response activities in Mexico and U.S. preparedness efforts. Through collaboration with our partners at the U.S. Centers for Disease Control and Prevention (CDC), U.S. Food and Drug Administration (FDA), U.S. Department of the Interior, and more, screwworm.gov has targeted resources for a wide range of stakeholders (for example, livestock producers, veterinarians, animal health officials, wildlife professionals, healthcare providers, pet owners, and the general public).  

Stopping NWS Spread in Mexico: Cross-Border Response and Collaboration 

In October, USDA conducted its most recent audit of NWS response activities in Mexico. Evaluators documented great progress in management of NWS, with robust outreach and education, effective emergency response and treatment protocols, and expansion of the workforce and surveillance. While there is still work to be done, USDA and SENASICA are committed to continued collaboration to implement the joint NWS Action Plan.  

In the event of case detection in a new (previously NWS-“Free”) location within Mexico, USDA teams are on the ground working alongside SENASICA counterparts to ensure treatment of affected animals, epidemiological tracing, local surveillance, and timely dispersal of sterile flies. The two isolated NWS cases in cattle in Nuevo León were categorized as “inactive” by SENASICA last month, after the animals received antiparasitic treatment and completed 21-day quarantines. No additional NWS cases or non-sterile flies have been identified through intensive surveillance and trapping in Nuevo León or any other border State. As a precaution, APHIS will continue to direct the release of sterile flies across these northernmost detection areas until December. On November 11, an NWS case was detected in Guerrero State (502 miles from the U.S. border). As with the Nuevo León cases, USDA had a sterile fly dispersal plan in place within 12 hours of notification. As of November 21, the active case closest to the United States is in central Veracruz State, around 425 miles from the border.  

In early November, President Claudia Sheinbaum welcomed Secretary Rollins and her team to the Presidential Palace to discuss continued collaboration on shared challenges including NWS, and the Secretary attended a separate meeting with SENASICA to review bilateral response activities. USDA Under Secretary for Marketing and Regulatory Programs Dudley Hoskins accompanied Secretary Rollins on the trip and visited the State of Chiapas to review NWS containment practices and enforcement.  

Protecting the Border and Maximizing Our Readiness  

USDA personnel at the southern border continue to strengthen monitoring systems for NWS. APHIS has equipped counties along the southern border in Texas, Arizona, New Mexico, and California with approximately 120 monitored NWS-specific fly traps and over 7,000 fruit fly “double duty” traps. To date, over 30,000 U.S.-trapped flies have been submitted for NWS analysis; as of November 21, all flies have been confirmed to be negative. Meanwhile, APHIS Wildlife Services teams have examined at least 6,642 wild animals across 28 species in 120 U.S. counties, finding all to be free of NWS infestation.  

USDA and its Federal partners, including the U.S. Department of Health and Human Services, are also focused on the importance of increasing NWS awareness in the companion animal community, such that any potential infestations are quickly recognized and reported for further evaluation. On October 24, the FDA issued an Emergency Use Authorization for a drug (Credelio®, also known as lotilaner) to treat NWS infestations in dogs. In addition, FDA issued an Emergency Use Authorization today for Credelio CAT (lotilaner chewable tablets) to treat NWS infestations in cats. While the majority of American pets are at low risk of NWS due to their geographic location, those living near the U.S.-Mexico border or with travel histories to NWS-affected countries are more likely to be exposed. 

Should this pest enter the United States in the future, we have the tools, resources, and response plans in place to rapidly contain and eradicate it. Following the October 17 release of the draft NWS Response Playbook, APHIS Veterinary Services has been actively collecting stakeholder feedback to ensure the playbook’s operational useability and alignment with State and Federal response capabilities. The playbook and accompanying materials are living, dynamic documents that will continue to be refined in the coming months; comments and suggestions may be submitted to fad.prep.comments@usda.gov.   

Taking the Fight to Screwworm and Innovating Our Way to Success 

COPEG’s sterile NWS production facility in Pacora, Panama is operating at maximum production capacity (approximately 100 million flies per week). Aerial dispersal of sterile flies has continued uninterrupted in NWS-affected areas of southern Mexico, where our joint response activities with SENASICA are largely focused. On November 13, APHIS announced the opening of a new sterile insect dispersal center in Tampico (Tamaulipas State), allowing for aerial dispersal over the detection sites in Nuevo León and replacing the use of ground release chambers in that location. This investment represents an important step forward in the NWS response as it creates greater flexibility and predictability in our deployment of sterile insects across northern Mexico and along the border, if necessary. 

Construction is progressing on the sterile fly dispersal facility at Moore Air Base in McAllen, TX, and it is on track to be operational in early 2026. USDA also continues to work closely with the U.S. Army Corps of Engineers (USACE) on planning for the domestic production facility for sterile flies. In early November, COPEG hosted a team of technical experts from USACE, who were able to observe the production process firsthand and learn about facility requirements.  

USDA is in the process of finalizing details for the NWS Grand Challenge—up to $100 million of new funding to combat the pest and prevent its spread northward. We’re calling on innovators, researchers, and industry leaders to help us enhance sterile NWS fly production and strengthen preparedness. Potential projects might include: enhancement of sterile NWS fly production; development of novel NWS traps and lures; increased understanding of NWS therapeutics/treatments in animals; or other tools to bolster U.S. preparedness or response to NWS. Please monitor screwworm.gov and the APHIS stakeholder registry for updates on this opportunity.