The new world screwworm (Cochliomyia hominivorax) remains a top animal-health concern for the United States, Mexico and several Central American nations. Ongoing surveillance, targeted sterile-insect releases and coordinated trade policies are the core tools used to restrict the parasite’s spread. Recent developments—especially the reopening of a major U.S. cattle import gateway—provide a snapshot of how federal agencies and neighboring governments are adapting their strategies in real time.
Trade restrictions and protocol updates
Both import and export pathways are governed by USDA regulations. The agency maintains a public list of regions classified as affected by screwworm, and any temporary trade barriers are posted under the Animal Health Status of Regions portal. For detailed import requirements covering all livestock species, stakeholders can consult the Live Animal Imports guide, while exporters should reference the Live Animal Exports page for the latest prohibitions and conditions.
Douglas, Arizona port reopening and future plans
On August 24, 2026 USDA announced that the Douglas, AZ port would once again accept live cattle from Mexico. This decision follows a joint, science-based import protocol approved by both U.S. and Mexican authorities, emphasizing overlapping safeguards and rigorous risk assessments. The reopening marks the first step in a phased strategy to restore Southern border livestock trade, conditional on meeting milestones outlined in the bilateral Action Plan.
Success at Douglas will be reviewed before considering the re-activation of the Santa Teresa, NM and Columbus, NM ports for cattle, bison and horses. The timeline remains fluid; any newly identified risk in the Mexican states of Sonora or Chihuahua could pause the process, as post-opening audits may reveal heightened exposure.
Mexico’s sterile-insect program and case reporting
Mexico’s National Service of Health, Food Safety and Quality (SENASICA) continues to adjust the sterile-insect release polygon to maintain broad suppression of the pest. The release area is refreshed as needed, based on scientific modeling and field observations, to prevent the worm from establishing in fresh territories. A case is considered “active” at diagnosis; after 15 days, officials reassess. If no new wounds or larvae are detected, the case is deemed “inactive”. Updated maps and daily case listings (published at 5 p.m. ET on business days) keep the public and industry partners informed.
Central American coordination
In the lower Central American corridor, the Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG) provides the most recent data on regional infestations. Their website hosts up-to-date summaries of control measures, sterile-insect releases and cross-border collaboration efforts, ensuring that each country’s response aligns with the overarching North-American strategy.
All parties stress the importance of immediate reporting when suspicious wounds, maggots or infestations appear in livestock or humans. Rapid notification allows USDA’s Animal and Plant Health Inspection Service (APHIS) to act quickly, limiting further spread and protecting both animal welfare and agricultural commerce.
