Mexico Produces Millions of Sterile Flies Weekly to Fight 34,000 Screwworm Cases
Updated
Updated · The New York Times · Sep 2
Mexico Produces Millions of Sterile Flies Weekly to Fight 34,000 Screwworm Cases
3 articles · Updated · The New York Times · Sep 2
Summary
Metapa’s newly refurbished plant has become Mexico’s main weapon against the country’s first major screwworm outbreak in decades, breeding and sterilizing millions of flies a week for release into the wild.
The strategy aims to collapse the flesh-eating pest’s population because sterile males mate without producing offspring, gradually reducing infestations that have spread since the first case was detected in November 2024.
More than 34,000 cumulative cases have been recorded in all but two of Mexico’s 32 states, turning the outbreak into a nationwide livestock threat.
The resurgence has already strained cattle trade and prices: the U.S. shut its border to Mexican cattle imports last year, and the disruption has contributed to higher U.S. beef prices.
Officials say the comeback of a parasite largely eradicated by the early 2000s is expected to cost billions of dollars in losses and control measures.
As flesh-eating screwworms breach the US border, will releasing millions of lab-grown sterile flies be enough to save the cattle industry?
With illegal smuggling driving a flesh-eating parasite north, can a newly reopened US border truly remain safe from infestation?
Screwworm Resurgence 2026: The Race to Produce 500 Million Sterile Flies per Week for Eradication
Overview
The 2026 screwworm outbreak began after the parasite breached the Darien Gap in 2023, spread into Mexico in 2024, and eventually reached Texas in 2026. Years earlier, the shutdown of the Chiapas sterile fly facility left only one production center in Panama, eliminating redundancy and weakening rapid response. When the outbreak hit, the U.S. faced a massive deficit in sterile fly production, prompting emergency funding and new facilities in Mexico and Texas. Traditional sterile insect techniques are inefficient, but new male-only genetic strains like NovoFly promise to double production and improve eradication, offering hope for regaining control.