A scary bug problem is making news near the US-Mexico border. Mexico found a case of screwworm in cows just 70 miles from the United States. This flesh-eating parasite was wiped out in the US back in the 1960s. But now, it’s back in parts of Mexico. Farmers and officials are on high alert. The find happened in Nuevo León state, in northern Mexico. It’s the closest case yet to the border. This could hurt cattle trade and farm jobs if it spreads.
The news came on Sunday, September 22, 2025. Mexico’s agriculture ministry shared the details. An 8-month-old cow had the screwworm. The cow came from Veracruz, a spot with earlier outbreaks. Out of 100 cows in the group, only this one was sick. The city of Sabinas Hidalgo is where they spotted it. It’s a small place, but its location is key—less than 70 miles from Texas.
Before this, the farthest north case was in Veracruz in July. That was 370 miles from the border. Now, things feel closer to home for US ranchers. Screwworm flies lay eggs in cuts on animals. The babies, called larvae, eat living flesh. It causes big pain and damage. The grown flies then drop to the dirt, hide, and turn into new bugs. It’s a fast cycle that can kill cows, sheep, and even deer.
Mexican leaders acted quick. They checked all the cows for wounds and bugs. Everyone got a shot of ivermectin, a medicine that fights parasites. Julio Berdegué, Mexico’s agriculture secretary, posted on social media Monday. He said the government is watching close and working with the US. He even talked to Brooke Rollins, the US Agriculture Secretary, on Sunday.
In the US, Rollins called it a “national security priority.” The USDA has spent tons of money to stop it. They make millions of sterile flies in a lab in Panama. These flies can’t make babies, so they cut down the bug numbers. The US gave Mexico tools and help. This year, they added $30 million for a new fly factory near Mexico and Guatemala. They’re also building one in Texas to spread sterile flies.
Both countries check thousands of traps along the border since July. No bugs found yet. But they’re ready with new plans. President Claudia Sheinbaum of Mexico spoke about it Monday. A USDA team just visited Mexico. They checked the steps being taken. Sheinbaum said, “We’re doing everything in our power to prevent further contamination.” The team will share their report soon. She wants decisions based on facts, not guesses.
This outbreak started in Central America months ago. It hit Mexico’s Oaxaca and Veracruz states earlier this year. The US shut southern ports to cattle, bison, and horses from Mexico. In July, Sheinbaum called that “exaggerated” after one case in Veracruz. Ports are still closed. But she stressed teamwork. “The important thing is that there was an agreement with the US government: that the decision to open or close the border would not be based on a series of technical indicators,” she said.
Why Screwworm Is Such a Threat
Screwworm isn’t just a bug—it’s a farm killer. Here’s why it scares experts:
- Fast Spread: One fly can lay hundreds of eggs. Larvae grow quick and drop to make more flies.
- Hurts Animals Bad: They eat deep into wounds. Cows get sick fast, lose weight, or die. Treatment costs a lot.
- Hits Trade: US bans imports to stay safe. Mexico loses billions in cattle sales each year.
- Old Enemy: Eradicated in the US in 1966 with sterile flies. But climate change and travel bring it back.
- Human Risk Too: Rarely, it can infect people, especially kids with cuts.
In Panama, they found larvae in cows this June. A photo shows the worm-like bugs in a dish. It’s gross but shows the real danger.
How Countries Are Fighting Back
The US and Mexico team up strong. The sterile fly method works well. Labs raise bugs, zap them with radiation, and release them. Males mate with wild females, but no babies come. It’s like birth control for flies.
Mexico adds checks at farms and roads. They train vets to spot signs early. The US helps with money and tech. In Central America, they build awareness. Farmers learn to watch wounds and report fast.
Sheinbaum’s team hopes the USDA visit leads to open ports soon. “They are about to issue their ruling shortly,” she said. If traps stay clean, trade could restart.
What This Means for Farmers and Food Prices
US ranchers worry. A screwworm jump could infect herds. It would cost millions to fix. Mexico’s cattle industry is huge—over 30 million cows. Outbreaks slow growth and sales.
Food prices might rise if beef gets scarce. Tacos, steaks, and burgers could cost more. Tourists in border towns feel it too. Safer farms mean steady supply.
Experts like Alexa Robles-Gil, a science reporter, watch close. She’s part of The New York Times’ fellowship for young journalists. Her work highlights how bugs affect daily life.
Climate plays a role. Warmer weather helps flies move north. Droughts stress animals, making wounds more likely. Solutions need global effort.
Hope on the Horizon
This case is early, but close. Quick action gives hope. No flies in US traps is good news. With $30 million more from the US, tools improve.
Berdegué and Rollins’ talk shows trust. Sheinbaum pushes for fair rules. If the USDA says yes, borders reopen. Farmers breathe easy.
Screwworm reminds us: Borders don’t stop bugs. Teamwork does. As fall starts, eyes stay on the traps. For now, the line holds. But vigilance wins.
