Mexico and U.S. Confront Screwworm to Restore $3 Billion Cattle Trade

Mexico’s Secretariat of Agriculture announced on May 28, 2025, an agreement with the U.S. to resume cattle exports, vital for $3 billion in annual trade.

A screwworm outbreak, starting in Chiapas in November 2024, led to U.S. import bans in May 2025. The pest, spreading from Central America, threatened livestock and markets.

The New World screwworm’s larvae devour livestock tissue, often killing hosts within weeks. Mexico reported 369 cases by March 2025, including six human infections. The U.S., screwworm-free since 1966, halted imports, citing cases in Oaxaca and Veracruz near export zones.

Mexico invested $8.5 million, releasing 90 million sterile flies weekly, cutting cases by 51.8% since April 2025. Bans cost producers $11.4 million daily, stranding 300,000 cattle. A USDA team will inspect Mexico’s efforts in June 2025 to confirm progress.

The U.S. pledges $21 million for a Chiapas sterile fly plant, producing 60-100 million flies weekly by November 2025. Enhanced border controls isolate northern export zones.

Illegal cattle smuggling from Guatemala, where 40,000 regional cases emerged, drove the outbreak. Mexico exported 1.3 million cattle in 2023-2024, supporting U.S. beef markets.

The halt slashed exports by 60%, spiking prices amid U.S. herd shortages. Chihuahua producers lost $25-30 million weekly, facing mounting debts and market uncertainty.

Tensions arose over U.S. delays in funding the Chiapas plant and limiting Panama’s sterile fly supplies. The agreement eases concerns, but border security and construction timelines remain hurdles. Both nations push for rapid trade restoration to stabilize economies.