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Science
Jun 19, 2026
Analyzed by Glm 4.7 Flash

First US Screwworm Case in 60 Years: A Catastrophic Eradication Failure

AI Summary
The US Department of Agriculture confirmed the first case of New World screwworm in a Texas calf in over 60 years, signaling a catastrophic failure of the long-standing eradication program. This re-emergence, traced back to Central America via Mexico, poses a dual threat to the American livestock industry and public health, potentially driving beef prices to record highs.

The Re-Emergence of a 1960s Eradication Failure

The New World screwworm, a flesh-eating parasite previously declared eradicated in the US in 1966, has returned with a vengeance. The US Department of Agriculture confirmed the first case in 60 years on Wednesday, finding the larvae in a three-week-old calf in LaPryor, Texas. Experts believe the pest evaded biological barriers by travelling from Central America to Mexico, where cases surged by 53% between mid-July and mid-August 2025.

Economic and Epidemiological Data

The return of this pest carries severe financial implications for the American agricultural sector. The USDA predicts that a US outbreak could cost the Texas economy up to $1.8bn in losses. Furthermore, the parasite has already impacted human populations, with Mexico confirming 41 human cases last year, primarily in the state of Chiapas.

  • 53% increase in animal cases in Mexico (July-Aug 2025)
  • $1.8bn projected economic loss for Texas
  • 41 human cases reported in Mexico in the previous year

A Threat to Food Security and Public Health

The impact extends beyond animal welfare to the national food supply. Washington has already halted cattle imports from Mexico for the past year, contributing to rising beef prices. A full US outbreak would further tighten the supply chain, as ranchers struggle to treat the larvae manually—a painful and labor-intensive process that most modern farmers lack the experience to perform.

Public health experts also warn of a secondary risk to vulnerable populations. Dr Timothy Goldsmith noted that homeless individuals are particularly susceptible due to exposure and limited access to hygiene and medical care.

The Road Ahead: Sterile Fly Strategy vs. Market Volatility

The immediate response involves establishing a 20km quarantine zone and a program of sterile male release, which was the successful method used in the 1960s. However, the long-term outlook remains uncertain. Experts point to disruptions in sterile-fly programs during the COVID-19 pandemic and increased cross-border movement as key factors in the re-emergence. As the industry grapples with a multi-decade low in cattle herds, the return of screwworm threatens to exacerbate inflation in the meat sector.