Summary
The New World screwworm, a flesh-eating livestock parasite eradicated from the United States in the 1960s, was confirmed in Texas in June 2026. The outbreak comes as the U.S. cattle herd sits at a 74-year low, Mexican cattle imports remain restricted, and beef prices are already near record highs. If the outbreak expands, it could increase production costs, tighten cattle supplies, and place additional upward pressure on beef prices for American consumers.
Key Takeaways
- The New World screwworm returned to the United States on June 3, 2026, with the first confirmed case in Texas.
- The parasite threatens cattle production by damaging livestock and increasing treatment and containment costs.
- The U.S. cattle herd is already at its lowest level in 74 years after years of drought and herd liquidation.
- Mexican cattle import restrictions have removed approximately 795,000 head from the U.S. supply chain.
- USDA projects beef and veal prices will rise 12.1% in 2026, even before accounting for a larger outbreak.
- Families can reduce their exposure to rising food costs by building long-term food and protein reserves now.
What Is the New World Screwworm?
The New World screwworm is not a worm at all—it’s the larval stage of a parasitic fly whose damage is far worse than its name suggests.
Female screwworm flies lay eggs in the open wounds of warm-blooded animals.
Once those eggs hatch, hundreds of larvae use sharp mouthparts to burrow into living flesh—feeding, enlarging the wound, and eventually killing the host if left untreated.[1]
A tiny scrape, a healing ear tag, a fresh brand on a calf's flank can become a gaping, maggot-filled wound within days.
The screwworm was eradicated from the United States in the 1960s through a method still in use today: Releasing sterile male flies that mate with wild females, producing infertile eggs and collapsing local populations.[1]
That eradication was considered one of the great achievements in American agricultural history.
Then in 2023, cases began appearing in Panama and Costa Rica.
According to CIDRAP at the University of Minnesota, the parasite has since spread north through every country in Central America and deep into Mexico—with at least 185,000 animal cases and more than 2,100 human cases now confirmed across the region.[2]
By June 3, 2026, it crossed into the United States.
The USDA confirmed the first case in a 3-week-old calf in Zavala County, Texas.
By June 12, nine cases had been confirmed in the United States—8 in Texas and one in New Mexico. Affected animals included cattle, goats, and a dog.[3]
The screwworm cannot fly more than 12 miles on its own.
But it can travel great distances inside a living host—making animal movement one of the primary drivers of geographic spread.
The food supply is not at risk.
USDA has confirmed that screwworm-infected animals are identified during inspection, and no contaminated product enters commerce.
But the threat to American cattle herds—and to the beef prices families pay at the grocery store—is very real.
Why Are Beef Prices Already So High?
Beef prices were already at historic highs before the screwworm arrived. The screwworm didn't create this problem—it landed on top of one already years in the making.
According to the USDA Economic Research Service, the U.S. cattle herd has been in contraction for seven consecutive years—from 2020 through 2026—producing successively smaller calf crops each season. [4]
The result: Record-high beef and feeder steer prices are projected for 2026, and the USDA warns that elevated retail beef prices could persist for several years.[4]
The numbers are stark.
According to the American Farm Bureau Federation, citing USDA data, the total U.S. cattle and calf inventory stood at 86.7 million head as of January 2025—the lowest in 74 years. [5]
The beef cow herd, which is the breeding population that produces future supply, had fallen to levels not seen since the early 1960s. [5]
Years of Drought Forced Ranchers to Liquidate
The primary driver of that collapse was drought.
Persistent, multi-year drought across the Great Plains and Western United States beginning in 2020 decimated grazing land and drove feed costs to levels many ranching families couldn't absorb.
According to the American Farm Bureau Federation, ranchers were forced to sell off breeding stock refined over decades—losses that could take years to recover. [5]
When land finally began to recover, ranchers faced a financial wall.
Rebuilding a herd requires holding back breeding heifers instead of sending them to slaughter—a costly, years-long commitment in an environment of record-high operational costs and market uncertainty.
The supply pipeline has been running on empty, and there is no quick fix.
Demand for Beef Has Not Let Up
What makes this worse is that Americans have not stopped buying beef. Consumer demand has remained strong despite record prices.
According to the USDA ERS, beef and veal prices were 14.8% higher in April 2026 than in April 2025—and are projected to rise 12.1% for the full year. [6]
The combination of shrinking supply and stubborn demand is what drives prices to levels most families have never seen at the checkout line.
How Does the Mexico Cattle Import Ban Affect Beef Prices?
The Mexico supply chain problem has made an already tight market tighter, and the screwworm is at the center of it.
The U.S. typically imports over one million cattle from Mexico every year. [1]
These animals are fed and fattened on American farms for 5 to 6 months before slaughter, representing a critical input into the domestic beef supply chain.
That pipeline has been disrupted—repeatedly and severely—by the screwworm threat.
According to the American Farm Bureau Federation, the U.S. first closed the southern border to cattle, bison, and equine imports from Mexico in November 2024 as a precautionary measure.
The border reopened in February 2025, closed again in May as screwworm detections moved north, and has remained closed since. [5]
The result was a staggering supply gap.
According to the American Farm Bureau Federation, imports of cattle from Mexico between November 2024 and August 2025 ran approximately 795,000 head below the same period the prior year. [5]
Feedlots in South Texas that depended on Mexican feeder calves faced empty pens. Some operations closed entirely.
Mexican cattle are not just a volume number—they fill a specific role in the supply chain.
According to Reuters, the closure contributed directly to rising beef prices by keeping calves out of U.S. feedlots at a time when the domestic herd was already at a multi-decade low. [1]
With the screwworm now confirmed on U.S. soil, that border is unlikely to reopen soon. The supply gap that already exists will persist — and potentially widen.
What Is the Economic Impact of a Major Screwworm Outbreak?
A limited outbreak is manageable. A widespread one is a different story entirely.
Higher Costs for Producers
Treating a screwworm infestation is not simple.
Infestations can be cured, but treatment involves manually removing hundreds of larvae and thoroughly disinfecting wounds. It is time-consuming, labor-intensive, and expensive. [1]
After 6 decades without this pest, most cattle ranchers no longer have the experience or the tools to diagnose and treat screwworm quickly.
Every infestation adds veterinary fees, additional labor, wound-management supplies, and herd monitoring costs.
Those costs fall directly on producers who are already operating in one of the most financially stressful cattle markets in a generation.
As David Anderson, livestock economist at Texas A&M University, put it: "This is a pest we don't want back. This is a bad thing." [1]
Supply Chain Disruptions
The screwworm spreads primarily through the movement of infested animals, not through fly mobility alone.
Quarantine zones have already been established around confirmed cases.
As of June 12, the USDA has implemented movement controls and surveillance protocols in the affected counties, with all warm-blooded animals in infested zones prohibited from leaving without prior authorization. [3]
If the outbreak spreads, those movement restrictions expand with it.
More counties locked down means more cattle unable to reach feedlots or processing facilities on schedule.
Fewer cattle processed means less beef reaching grocery stores. And less beef at a time of already record-low supply means one outcome: higher prices.
The Billion-Dollar Risk
The scale of potential economic damage has been calculated.
The USDA estimated that a major screwworm outbreak in Texas would cost the state's economy $1.8 billion in livestock deaths, labor costs, and medication expenses. [1]
That figure was calculated before the outbreak was confirmed on U.S. soil. It represents a scenario the government has spent more than a year trying to prevent—and now must contain.
The sterile fly program is the primary defense.
The USDA has released more than 130 million sterile male flies in Texas since January. [3]
A production facility in Texas is under construction, with full operational capacity not expected until late 2027. [1]
Until that facility is online, the response depends on flies shipped weekly from a facility in Panama.
What Does This Mean for Beef Prices?
The direct answer: Beef prices are not coming down anytime soon, and this makes the timeline longer.
According to the American Farm Bureau Federation, the U.S. cattle inventory will likely not expand until at least 2028. [5]
That's the earliest point at which herd growth could begin translating into meaningfully more beef at the store.
Between now and then, tight supply meets strong demand every single week.
The Mexico border closure has already removed a significant number of feeder cattle from the pipeline.
Every month that border stays closed extends the supply deficit further into the future.
And now the screwworm adds yet another pressure.
Even if the current outbreak is contained quickly, ranchers across Texas and beyond face new surveillance requirements, additional labor, and the psychological weight of a pest they've never had to manage.
Those costs flow downstream.
Beef prices were up 14.8% in April 2026 compared to the year before, according to USDA. [6]
The USDA projects a 12.1% increase for the full year. [6]
That was the forecast before the recent screwworm cases were confirmed on American soil.
The grocery store is the last place these pressures show up.
By the time you feel it at the checkout line, the problem has already been building for months.
How Can Families Prepare for the Coming Beef Shortages?
The beef supply crunch isn't going to resolve itself in a month or a season. The responsible move is to act before prices climb further…and before availability tightens.
Focus on Food Security, Not Panic - The current outbreak is relatively small, and officials have successfully contained screwworm before. The goal isn't to expect empty shelves. The goal is to reduce your dependence on a food system facing multiple pressures at the same time.
Build Protein Reserves First - Most people focus on calories. Protein is usually the harder and more expensive part of food preparedness. Consider freeze-dried meats, whole egg powder, canned meats, beans, and other shelf-stable protein sources. Freeze-dried beef that stores for up to 30 years gives you a long-term hedge against rising prices without relying on a freezer or refrigeration.
Stock Your Freezer Now - Beef bought today is beef bought before the next price increase. If a portion of your protein plan relies on fresh or frozen beef, buying in bulk now, while prices and availability are still manageable, costs less than buying the same amount after a larger outbreak tightens supply further.
Buy Before Demand Spikes - Food supply issues often become obvious only after prices have already moved. Building reserves gradually gives you more flexibility and usually costs less than reacting later.
The screwworm arrived on American soil on June 3, 2026. The response is underway. Whether it works — and how quickly — is still unknown.
What is known is that the beef supply was already stretched thin before this started. And the families best positioned for what comes next are the ones who didn't wait to find out how bad it would get.
What steps are you taking to protect your family's food security as beef prices continue to rise? Share your thoughts in the comments below.
In liberty,
Jake SeaWolf
Preparedness Advisor, My Patriot Supply
Sources
[1] Heather Schlitz, Reuters.How flesh-eating screwworms in cattle could raise US beef prices.
Updated June 4, 2026. https://www.reuters.com/business/healthcare-pharmaceuticals/how-flesh-eating-screwworms-cattle-could-raise-us-beef-prices-2026-06-04/
[2] CIDRAP, University of Minnesota.How to Protect Outdoor Pets from New World Screwworm.
2026. https://www.cidrap.umn.edu/new-world-screwworm/how-protect-outdoor-pets-new-world-screwworm
[3] Tara Brolley, CBS Austin.New World Screwworm Cases Climb to Nine in U.S. with Two More Confirmed in Texas.
June 12, 2026. https://cbsaustin.com/news/local/new-world-screwworm-cases-climb-to-nine-in-us-with-two-more-confirmed-in-texas
[4] USDA Economic Research Service.Livestock Production Cycles Affect Long-Term Price Outlook for Cattle, Hogs, and Chickens.
March 17, 2025. https://www.ers.usda.gov/amber-waves/2025/march/livestock-production-cycles-affect-long-term-price-outlook-for-cattle-hogs-and-chickens
[5] American Farm Bureau Federation — Market Intel.Economics of U.S. Beef and Cattle Market.
2025. https://www.fb.org/market-intel/economics-of-u-s-beef-and-cattle-market
Bullish Cattle Report Does Not Indicate Herd Expansion. December 4, 2025. https://www.fb.org/market-intel/bullish-cattle-report-does-not-indicate-herd-expansion
[6] USDA Economic Research Service.Food Price Outlook — Summary Findings.
May 2026. https://www.ers.usda.gov/data-products/food-price-outlook/summary-findings
[7] Katie Glanton, The National Desk.As Screwworm Spreads in Texas, Tennessee Expert Urges Awareness, Not Panic.
June 16, 2026. https://thenationaldesk.com/news/americas-news-now/as-screwworm-spreads-in-texas-tennessee-expert-urges-awareness-not-panic-new-world-screwworm-cattle-health-university-of-tennessee-entomologist-livestock-disease-concerns-texas-cattle
