A parasitic fly that lays eggs in living flesh — the larvae then eat the host from the inside out — is marching steadily northward through Central America toward the United States. The US government spent decades and enormous resources pushing it back. Then the Trump administration spent the last year gutting the agencies responsible for making sure it never came back.
Meet the Screwworm, Your New Least Favorite Bug
The New World screwworm, Cochliomyia hominivorax, is exactly as horrifying as the name suggests. The fly lays eggs in open wounds on warm-blooded animals. The maggots hatch and burrow inward, feeding on living tissue. Left untreated, a screwworm infestation kills. Livestock. Wildlife. In rare cases, people.
The US actually won this fight once. A massive, sustained eradication campaign launched in the 1950s used a technique called the Sterile Insect Technique — releasing enormous numbers of radiation-sterilized male flies so they outcompete fertile ones, crashing the population over generations. It worked. By 1982, screwworm was eliminated from the continental United States. A barrier zone was painstakingly pushed further and further south over the following decades, all the way down into Panama.
For more than forty years, that barrier held. Ranchers stopped losing cattle to a parasite that had once cost the industry hundreds of millions of dollars annually. Wildlife populations recovered. The screwworm became, for most Americans, someone else's problem in someone else's hemisphere. That's over now.
The Bug Is Back and It's Been Moving Fast
According to The Hill, experts have been tracking the parasitic fly as it moved steadily northward through South and Central America. It has already been detected in Mexico, which is a very short trip from Texas, Arizona, and New Mexico. US livestock and wildlife are not adapted to this threat the way animals in endemic regions are. An uncontrolled reintroduction would be catastrophic.
The USDA has been scrambling. Officials are reportedly reaching back to the same sterile insect releases that worked in the 1950s, which is either a reassuring sign that proven methods still exist, or a slightly alarming sign that the federal government is responding to a 2026 biosecurity crisis with a playbook written during the Eisenhower administration. Possibly both.
The response requires coordination, personnel, monitoring infrastructure, and funding. It requires exactly the kind of standing government capacity that can't be conjured from nothing when a crisis arrives at the border. And that is precisely where the story gets worse.
This Is What Happens When You Gut the USDA
The Trump administration and its DOGE operation spent the early part of 2025 treating the federal workforce like a renovation project where the goal was maximum demolition. The USDA absorbed thousands of job cuts. Inspectors, researchers, field agents, animal health officials — the people who do the slow, unglamorous, absolutely essential work of keeping parasites and pathogens from crossing US borders got pink slips or buyouts.
The Hill reports that the screwworm situation is now directly testing US readiness in the aftermath of those cuts. That's a polite way of saying that the government fired a lot of the people whose job it was to handle exactly this kind of thing, and now a flesh-eating parasite is heading north to find out how serious we were about that decision.
This is the part where someone in the administration will say the cuts were about efficiency and eliminating waste. It is genuinely difficult to identify the efficiency gains from not having enough agricultural inspectors to monitor a parasitic fly infestation at the southern border. But perhaps that math makes sense to someone who has never seen what a screwworm does to a calf.
The Cattle Industry Is Watching Very Closely
American ranchers, particularly in the Southwest and South, have a long institutional memory about screwworm. The older ones remember the eradication campaign. They remember what the fly cost the industry before the barrier was established. This is not abstract for them.
A reestablishment of screwworm in the US would hit cattle producers first and hardest. We are talking about an industry that is already dealing with drought, elevated feed costs, and a herd that has been shrinking for years. Adding a parasitic fly that requires active wound monitoring of every animal, kills untreated livestock, and spreads through wildlife populations would be genuinely ruinous for ranchers operating on thin margins.
The irony that a substantial portion of those ranchers voted enthusiastically for the administration that cut the agency responsible for protecting them from this exact threat is not something we will labor over at length. The irony speaks. We don't need to narrate it.
Panama Held the Line. For a Long Time.
It's worth understanding what it actually took to keep screwworm at bay for forty-plus years. The USDA maintained a sterile fly production facility in Panama for decades. Planes flew regular missions dropping sterile insects along the barrier zone. Monitoring networks tracked any reemergence. This was not a one-time fix. It was continuous, active, funded management of a biological threat.
According to The Hill, officials are now working to beat back the current advance using many of those same methods. The question is whether the staffing and infrastructure to execute those methods at scale still exists in a form capable of responding to a fast-moving crisis. You don't rebuild that capacity in a week. You don't hire your way back to full operational readiness before a fly crosses a river.
The screwworm barrier was one of American agriculture's genuine success stories. A bipartisan, multi-decade government program that saved billions of dollars and protected animals across an entire continent. Exactly the kind of thing that looks like "bureaucratic overhead" right up until the moment it isn't there anymore.
The Dingo Take
Here's the thing about government capacity: it doesn't feel like anything when it's working. The screwworm barrier held for over forty years, which means an entire generation of American ranchers and policymakers grew up with no lived experience of what the fly actually does to a herd. That made it easy to look at USDA headcount and see "waste." Fly monitoring infrastructure and sterile insect programs don't generate headlines. They just quietly prevent catastrophes that never happen, right up until they do.
The Trump administration and its DOGE chainsaw operation made a very deliberate choice about what kind of federal government they wanted. Smaller, faster, less "bloated," unburdened by all those scientists and inspectors and field personnel running around doing things that couldn't be explained in a tweet. That choice has consequences that are now literally crawling toward Texas. Nobody should be surprised. The people who warned this would happen were, of course, the people who got fired.
A flesh-eating parasite marching toward the American Southwest because the administration gutted the agency responsible for stopping it is not a metaphor. It is not a think-piece about institutional knowledge or the value of government expertise. It is a specific, preventable, ongoing disaster with a paper trail of personnel decisions attached to it. Pay attention to what happens next, because whatever the response looks like, it will tell you exactly how much damage was actually done.
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