US Launches 105 Million Dollar Campaign as Screwworm Fly Spreads in Southern States

The United States Department of Agriculture announced on Thursday a rapid increase in cases of the New World screwworm fly, with confirmed infestations rising by more than 50 percent within a single week. The parasite, which lays eggs in open wounds of living animals where larvae feed on tissue, has been detected in livestock and domestic animals across Texas, Arizona, and New Mexico.

The infestation marks a resurgence of a pest that had been declared eradicated in the United States in 1966 following a large-scale eradication campaign. That historical program relied on releasing sterile male flies into the wild to interrupt the insect's reproductive cycle. According to the USDA, more than 60 new cases have been recorded in southern states over the past 30 days, while adult flies captured in monitoring traps indicate broader active populations in the region.

The current spread follows an outbreak initially reported in Panama and Costa Rica in 2023, which subsequently moved northward through Central America into Mexico. Data cited by agricultural authorities shows that by October 2026, Mexico had logged over 209,400 infected animals and more than 2,850 human cases. Despite the human infections reported south of the border, the USDA assessed the immediate risk of transmission to humans within the United States as very low.

To mitigate the economic threat to livestock producers, federal authorities have allocated approximately 105 million dollars to contain the outbreak. Response measures include restrictions on animal movements out of affected zones and the aerial deployment of millions of sterile male flies. The USDA has also established live data tracking to monitor the movement of the parasite across affected counties.

Written by Christiane Hofreiter christiane.hofreiter@alpineweekly.com