• Home
  • Latest
  • Fortune 500
  • Finance
  • Tech
  • Leadership
  • Lifestyle
  • Rankings
  • Multimedia
Environmentmeat

Flesh-eating parasite tears through Mexican cattle as Texas braces for ‘devastating pest’

By
Fernando Llano
Fernando Llano
,
Fabiola Sánchez
Fabiola Sánchez
, and
The Associated Press
The Associated Press
Down Arrow Button Icon
By
Fernando Llano
Fernando Llano
,
Fabiola Sánchez
Fabiola Sánchez
, and
The Associated Press
The Associated Press
Down Arrow Button Icon
August 5, 2025, 8:19 AM ET
Martín Ibarra Vargas
Martín Ibarra Vargas points to his corrals at his small ranch in Hermosillo, Sonora state, Tuesday, July 29, 2025. AP Photo/Fernando Llano)

The United States’ suspension of live cattle imports from Mexico hit at the worst possible time for rancher Martín Ibarra Vargas, who after two years of severe drought had hoped to put his family on better footing selling his calves across the northern border.

Recommended Video

Like his father and grandfather before him, Ibarra Vargas has raised cattle on the parched soil of Sonora, the state in northwestern Mexico that shares a long border with the United States, particularly Arizona. His family has faced punishing droughts before but has never before had to contend with the economic hit of a new scourge: the New World Screwworm, a flesh-eating parasite.

U.S. agriculture officials halted live cattle crossing the border in July – the third suspension of the past eight months — due to concerns about the flesh-eating maggot which has been found in southern Mexico and is creeping north.

The screwworm is a larva of the Cochliomyia hominivorax fly that can invade the tissues of any warm-blooded animal, including humans. The parasite enters animals’ skin, causing severe damage and lesions that can be fatal. Infected animals are a serious threat to herds.

The U.S. Department of Agriculture calls it a “devastating pest” and said in June that it poses a threat to “our livestock industry, our economy, and our food supply chain.” It has embarked on other steps to keep it out of the United States, which eradicated it decades ago.

As part of its strategy the U.S. is preparing to breed billions of sterile flies and release them in Mexico and southern Texas. The aim is for the sterile males to mate with females in the wild who then produce no offspring.

The U.S. ban on live cattle also applies to horses and bison imports. It hit a ranching sector already weakened by drought and specifically a cattle export business that generated $1.2 billion for Mexico last year. This year, Mexican ranchers have exported fewer than 200,000 head of cattle, which is less than half what they historically send in the same period.

For Ibarra Vargas, considered a comparatively small rancher by Sonora’s beef-centric standards, the inability to send his calves across the border has made him rethink everything.

The repeated bans on Mexican cows by U.S. authorities has pushed his family to branch into beekeeping, raising sheep and selling cow’s milk. What he earns is just a fraction of what he earned by exporting live cattle, but he is trying to hold on through the lean times.

“Tiempos de vacas flacas” — times of the lean cows — as he calls them.

“At least it lets us continue” ranching, the 57-year-old said with a white cowboy hat perched on his head.

Reinvent to survive

Even as ranchers in Sonora intensify their efforts to make sure the parasitic fly never makes it into their state, they’ve had to seek new markets.

In the past two months, they’ve sold more than 35,000 mature cows within Mexico at a significant loss.

“We couldn’t wait any longer,” said Juan Carlos Ochoa, president of the Sonora Regional Cattle Union. Those sales, he said, came at a “35% lower price difference compared with the export value of a cow.”

That’s hard to stomach when beef prices in the U.S. are rising.

The U.S. first suspended cattle imports last November. Since then, more than 2,258 cases of screwworm have been identified in Mexico. Treatment requires a mix of manually removing the maggots, healing the lesions on the cows and using anti-parasite medicine.

Some ranchers have also started retail beef sales through luxury butcher shops referred to as “meat boutiques.”

There are other foreign markets, for example Japan, but selling vacuum sealed steaks across the Pacific is a dramatically different business than driving calves to U.S. feedlots. The switch is not easy.

An uncertain future

With his calves mooing as they ran from one end of a small corral to the other waiting to be fed, Ibarra Vargas said he still hasn’t figured out how he will survive an extended period of not being able to send them to the U.S.

The recent two-year drought reduced his cattle stocks and forced him to take on debt to save the small family ranch that has survived for three generations.

Juan Carlos Anaya, director of Agricultural Markets Consulting Group, attributed a 2% drop in Mexico’s cattle inventory last year to the drought.

Anaya said Mexican ranchers who export are trying to get the U.S. to separate what happens in southern Mexico from the cattle exporting states in the north where stricter health and sanitation measures are taken, “but the damage is already done.”

“We’re running out of time,” said Ibarra Vargas, who already laments that his children are not interested in carrying on the family business. For a rancher who “doesn’t have a market or money to continue feeding his calves, it’s a question of time before he says: ‘you know what, this is as far as I go.’”

__

Sánchez reported from Mexico City.

Subscribe to Fortune Gulf Brief. Every Tuesday, this new newsletter will deliver clear-eyed, authoritative intelligence on the deals, decisions, policies, and power shifts shaping one of the world’s most consequential regions, written for the people who need to act on it. Sign up here.
About the Authors
By Fernando Llano
See full bioRight Arrow Button Icon
By Fabiola Sánchez
See full bioRight Arrow Button Icon
By The Associated Press
See full bioRight Arrow Button Icon

Latest in Environment

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025

Most Popular

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Fortune Secondary Logo
Rankings
  • 100 Best Companies
  • Fortune 500
  • Global 500
  • Fortune 500 Europe
  • Most Powerful Women
  • World's Most Admired Companies
  • See All Rankings
  • Lists Calendar
Sections
  • Finance
  • Fortune Crypto
  • Features
  • Leadership
  • Health
  • Commentary
  • Success
  • Retail
  • Mpw
  • Tech
  • Lifestyle
  • CEO Initiative
  • Asia
  • Politics
  • Conferences
  • Europe
  • Newsletters
  • Personal Finance
  • Environment
  • Magazine
  • Education
Customer Support
  • Frequently Asked Questions
  • Customer Service Portal
  • Privacy Policy
  • Terms Of Use
  • Single Issues For Purchase
  • International Print
Commercial Services
  • Advertising
  • Fortune Brand Studio
  • Fortune Analytics
  • Fortune Conferences
  • Business Development
  • Group Subscriptions
About Us
  • About Us
  • Press Center
  • Work At Fortune
  • Terms And Conditions
  • Site Map
  • About Us
  • Press Center
  • Work At Fortune
  • Terms And Conditions
  • Site Map
  • Facebook icon
  • Twitter icon
  • LinkedIn icon
  • Instagram icon
  • Pinterest icon

Latest in Environment

At 75, Ted Turner told Fortune he gave himself 5 more years. He got 12—and spent them warning the world was ending
C-SuiteMedia
At 75, Ted Turner told Fortune he gave himself 5 more years. He got 12—and spent them warning the world was ending
By Ashley LutzMay 6, 2026
10 hours ago
This September 25, 2021 picture shows the deserted beach of Blue Bay in south-east Mauritius, known as one of the most beautiful beaches and for its marine park.
BankingImmigration
Tiny island nation unveils $1 million ‘Golden Visa’ for the wealthy—80% cheaper than Trump’s, with one catch: you’re renting
By Eleanor PringleMay 6, 2026
11 hours ago
Gas crisis? Kelp could be the biofuel answer to high gas prices, but only if the government removes some red tape
Environmentgas prices
Gas crisis? Kelp could be the biofuel answer to high gas prices, but only if the government removes some red tape
By The Associated Press, Ana Georgescu and Zoe BeketovaMay 6, 2026
13 hours ago
A Michigan farm town voted down plans for a giant OpenAI-Oracle data center. Weeks later, construction began
MagazineData centers
A Michigan farm town voted down plans for a giant OpenAI-Oracle data center. Weeks later, construction began
By Sharon GoldmanMay 6, 2026
20 hours ago
The Iran war’s oil shock causes a plastic shortage in Asia, squeezing industries and prompting a ‘Middle East plus one’ rethink of supply chains
Environmentsupply chains
The Iran war’s oil shock causes a plastic shortage in Asia, squeezing industries and prompting a ‘Middle East plus one’ rethink of supply chains
By Angelica AngMay 6, 2026
20 hours ago
Japanese workers commuting to the office
Successcorporate culture
Tokyo is throwing out its strict office dress code and asking workers to wear shorts amid the war in Iran energy crisis
By Emma BurleighMay 5, 2026
1 day ago

Most Popular

A Michigan farm town voted down plans for a giant OpenAI-Oracle data center. Weeks later, construction began
Magazine
A Michigan farm town voted down plans for a giant OpenAI-Oracle data center. Weeks later, construction began
By Sharon GoldmanMay 6, 2026
20 hours ago
Tokyo is throwing out its strict office dress code and asking workers to wear shorts amid the war in Iran energy crisis
Success
Tokyo is throwing out its strict office dress code and asking workers to wear shorts amid the war in Iran energy crisis
By Emma BurleighMay 5, 2026
1 day ago
Economists have found an answer to slowing cognitive decline: avoid retiring early, study finds
Economy
Economists have found an answer to slowing cognitive decline: avoid retiring early, study finds
By Sasha RogelbergMay 5, 2026
1 day ago
Dario Amodei spent last year warning of an AI white-collar bloodbath. Now he's changing the narrative
Economy
Dario Amodei spent last year warning of an AI white-collar bloodbath. Now he's changing the narrative
By Nick LichtenbergMay 5, 2026
1 day ago
Mark Zuckerberg once gave a Facebook engineer startup advice at 2 a.m. while 'hanging out with all the interns'—she quit and raised millions after
Success
Mark Zuckerberg once gave a Facebook engineer startup advice at 2 a.m. while 'hanging out with all the interns'—she quit and raised millions after
By Orianna Rosa RoyleMay 6, 2026
9 hours ago
Current price of silver as of Tuesday, May 5, 2026
Personal Finance
Current price of silver as of Tuesday, May 5, 2026
By Joseph HostetlerMay 5, 2026
2 days ago

© 2026 Fortune Media IP Limited. All Rights Reserved. Use of this site constitutes acceptance of our Terms of Use and Privacy Policy | CA Notice at Collection and Privacy Notice | Do Not Sell/Share My Personal Information
FORTUNE is a trademark of Fortune Media IP Limited, registered in the U.S. and other countries. FORTUNE may receive compensation for some links to products and services on this website. Offers may be subject to change without notice.