Flesh-Eating Screwworms Reappear Near Texas Border as Bi-National Prevention Program Falters
A historic U.S.-Mexico livestock program faces new challenges as invasive screwworms threaten the Texas ranching industry once again.
Editorial disclaimer: Opinions and analysis on Keep TX Red are editorial content — not statements of fact. See our editorial standards.
The New World screwworm, a devastating parasite that feeds on the living flesh of livestock and wildlife, has resurfaced as a significant threat to the agricultural stability of the Southern United States. Initially eradicated through a massive 20th-century biological campaign, the fly species is moving northward again due to shifts in international management strategies and environmental factors. Current reports indicate that the geographical buffer zones once maintained to keep the pest in Central America are beginning to fail, leading to concerns about an imminent re-infestation of Texas border counties.
Texas relevance
Texas is the nation's leading cattle producer, and a screwworm outbreak could cost the state's economy billions of dollars in lost livestock and mitigation expenses. Historically, Texas was the primary battleground for this pest until the sterile insect technique successfully pushed the population south of the Rio Grande in the 1960s. Any resurgence specifically targets the heart of the Texas ranching community, requiring local ranchers to increase surveillance of their herds to identify unexplained wounds or larval infestations.
Analysis
The resurgence of the screwworm is more than a biological anomaly; it is a warning about the dangers of bureaucratic complacency in international agricultural policy. For decades, the joint commission between the United States and Mexico, known as COMEXA, served as a model for how two nations could cooperate to eliminate a shared biological threat. However, as the immediate memory of the screwworm's devastation faded, so too did the urgency for robust funding and aggressive containment. By allowing the 'sterile fly' barrier to weaken, officials have essentially invited a known enemy back into domestic pastures. This situation reflects a broader trend where successful long-term programs are gutted for short-term fiscal gains, only to result in much higher costs when the original problem inevitably returns. For Texas, the political stakes are high. State leaders must weigh the cost of proactive subsidies for the Tuxtla Gutiérrez sterile fly plant against the catastrophic loss of cattle and deer populations. If the federal government does not stabilize the southern containment zones, Texas may be forced to shoulder the burden of emergency quarantines and localized eradication efforts. The screwworm does not respect borders, and its return highlights the inextricable link between international cooperation and the protection of the Texas economy. In past decades, the phrase 'screwworm' struck fear into the hearts of Texas cattlemen; today, that fear is turning into a call for immediate legislative and diplomatic action to fortify the biological defenses that have protected the state since the mid-20th century.
Source attribution
This story was reported using a public release from the Texas Monthly. Keep TX Red rewrote the coverage independently and links to the official statement for verification.
Frequently Asked Questions
- What makes the screwworm different from normal flies?
- Unlike most flies that feed on dead tissue, screwworms lay eggs in open wounds of living animals, where the larvae then consume the host's flesh.
- How was the pest originally defeated in Texas?
- Scientists used a method where millions of sterile male flies were released into the wild to prevent successful breeding, eventually collapsing the population.
- Can humans be affected by screwworms?
- Yes, while rare, screwworms can infect any warm-blooded animal, including humans, if they have an open wound or sore.
Official Sources
Take the next step
Browse the Newsroom →Read more about Keep Texas Red → Our full guide to what Keep Texas Red means and why Texans support it.
Related Articles
Get Texas updates delivered weekly.
Independent Texas reporting on politics, policy, and daily life. One email a week. Unsubscribe anytime.
Keep TX Red Newsroom
The Keep Texas Red Editorial Staff produces nonpartisan explainers, policy breakdowns, and educational resources to help Texans understand how their government works. All content is reviewed for accuracy and updated regularly.
About Keep TX Red →