Mexico and United States intensify response to screwworm outbreak in livestock

Mexico’s livestock sector has seen a sharp rise in cases of the screwworm parasite (Cochliomyia hominivorax), with the national report showing an 83.5% increase from 16,628 cases in March to 30,522 by late June 2026. The infestation, previously concentrated in southern states, has moved northward into Tamaulipas, Nuevo León, Coahuila and across the border into Texas. In the United States, federal agencies confirmed 20 animal infections in Texas and one in New Mexico, prompting a $105 million emergency fund, a state of emergency declaration by Texas Governor Greg Abbott, and large‑scale releases of sterile flies.

To bolster containment, Mexico and the United States are jointly investing in sterile‑fly production facilities: a $51 million plant in Metapa, Chiapas, to be inaugurated by U.S. Agriculture Secretary Brooke Rollins, and a $750 million Texas plant. Mexican authorities have also launched extensive training for veterinarians and launched a campaign that has already released nearly 7 billion sterile flies nationwide. Wildlife cases are being tracked, with the first confirmed screwworm infection in a black bear in Nuevo León.

The outbreak has halted Mexican calf exports to the United States and is driving coordinated federal‑state‑binational efforts to prevent further spread.