The Fly at the Border

A flesh-eating parasite once thought eradicated from the United States is creeping north again, testing what happens when a nation obsessed with efficiency cuts too deep.

At a cattle ranch outside Laredo, the smell of antiseptic mixes with dust and diesel as a veterinarian leans over the open wound of a cow, searching for signs of something America swore it had killed off decades ago: the flesh-eating screwworm. The larvae of this fly can strip a healthy animal to bone in days, and its return would gut the U.S. livestock industry. But this isn’t just a story about a parasite crawling back across the border. What’s creeping north isn’t just a parasite. It’s the consequence of policy decay, the kind you don’t smell until it’s too late. It’s about a government that’s been carving itself thin under the banner of “efficiency,” first led by Elon Musk’s Department of Government Efficiency (D.O.G.E.), the latest experiment in turning bureaucracy into a start-up. As the threat grows, the question writes itself: what happens when a nation obsessed with cutting the fat realizes it’s carved into muscle?

The New World screwworm (NWS) isn’t new. It’s a fly whose larvae feed on living flesh, turning wounded animals into dead remains. In the 1950s, the U.S. fought back with a massive eradication effort, releasing millions of sterile male flies to wipe out the species from Texas down to Panama. It worked. At its peak, the program released 150 million sterile flies a week and employed more than 3,000 technicians across the Americas. For half a century, the border held. But now the parasite is creeping north again, carried by livestock and wildlife crossing Mexico’s thinning line of defense. The USDA calls the risk “contained.” Ranchers along the Rio Grande aren’t buying it. They’ve heard this story before, and they know how it ends when Washington decides vigilance costs too much.

In D.C., that responsibility now falls to a government running on fumes. Budgets trimmed, oversight merged, inspectors stretched thin from the border to the lab. Agencies that once treated biosecurity as infrastructure now treat it as discretionary. On paper: modernization. In practice: a slow hollowing-out of the machinery built to stop outbreaks like this before they start. “We’ve done more with less for years,” says a USDA field inspector who asked not to be named. “But at some point, less just means you stop seeing what’s coming.” Federal officials call it reform. The people doing the work call it a gamble.

That machinery lives inside the U.S. Department of Agriculture, in programs most Americans will never hear about. APHIS field offices. Quarantine stations. A decades-old sterilization plant in Panama that still serves as the country’s biological firewall. Inspectors track livestock crossings, monitor traps, and file the data that separates safety from disaster. APHIS still maintains about 8,000 screwworm traps along the southern border and funds a permanent barrier zone in Panama, releasing more than 20 million sterile flies every week. When funding drops, those numbers fall. The new sterilization plant in Texas, meant to backstop Panama’s, was funded for barely 60% of its projected output in its first year, even as USDA listed the screwworm’s northward drift as “likely.” The border is vast. The insects are relentless. And efficiency doesn’t catch what it can’t see.

“In the old days, we had planes in the air every morning,” recalls retired screwworm technician Bill Faulkner. “Now you’ve got spreadsheets and wishful thinking."

When prevention fails, the bill doesn’t show up in a budget line. It shows up in quarantined herds, shuttered borders, and headlines about contaminated beef. One outbreak could drain nearly $2 billion from Texas alone and cost the national livestock industry more than $3 billion in its first year, resulting in higher plate costs for consumers across the country. It’s the kind of slow-motion crisis that doesn’t fit on a bumper sticker: too technical to grab attention, too expensive to ignore. The government calls it a manageable risk. The people in the field stopped calling it a risk years ago. They call it inevitable.

In 2016, an outbreak of NWS was confirmed in the endangered Key deer population in the Florida Keys, primarily on Big Pine Key and No Name Key. The final report by the U.S. Department of Agriculture logged roughly 145 cases (128 presumptive, 17 confirmed) among the Key deer and a few other domestic/wild animals.

In June of 2025, the U.S. confirmed a traveler-associated human case of NWS in a resident of Maryland who had recently traveled to Central America, in the El Salvador/Guatemala region. Health authorities note the risk to public health remains low. According to the USDA/APHIS fact sheet, as of 2025 there have been “no confirmed NWS detections in U.S. livestock this year."

In May of 2025, the USDA suspended all live imports of cattle, horses, and bison from Mexico through the southern border ports due to the northwest spread of NWS.

The screwworm isn’t political. It doesn’t care about party lines or budget ceilings. It’s proof that nature doesn’t wait for efficiency audits. America built a system that could see danger coming and meet it head-on, then spent decades dismantling it in the name of cost cutting and modernization. Now a parasite that eats living flesh is testing what’s left.

The truth is simple and ugly: you can’t starve the government and then expect it to protect you.