A Flesh-Eating Menace Crosses Our Border
Imagine a tiny fly that lays eggs in open wounds, hatching maggots that eat living flesh. This is the screwworm, a gruesome parasite once wiped out in America but now creeping back. Recently, a Maryland resident brought this pest home from El Salvador, sparking fears it could spread to our livestock and pets. This shocking case has farmers and health officials on edge, but there’s more to this story. Keep reading to uncover how this threat could hit our food supply and what’s being done to stop it.
What Is the Screwworm?
The New World screwworm is a dangerous fly. Its larvae burrow into the flesh of animals like cattle, dogs, and even humans. Unlike other maggots, these pests attack healthy tissue, causing painful sores that can kill if untreated. Female flies lay hundreds of eggs in wounds, and within hours, larvae start eating. This leads to deep, infected wounds. In the past, screwworms cost U.S. farmers billions. Therefore, their return is a serious concern.
How Did Screwworm Return?
Screwworms were eradicated from the U.S. in 1966 using sterile flies to stop breeding. A barrier in Panama kept them out for decades. However, in 2023, cases spiked in Panama, spreading to Mexico by 2024. Illegal cattle trade and warmer climates likely helped the pest move north. Now, it’s just 700 miles from Texas. Meanwhile, the U.S. has banned Mexican livestock imports to protect our herds.
A Shocking U.S. Case
In August 2025, a Maryland traveler returned from El Salvador with screwworm larvae in a wound. Doctors removed the maggots, and the patient recovered. Thankfully, no spread occurred. Still, this case alarmed health officials. The CDC says the risk is low, but travelers to Central America must watch for sores or maggots. Prompt treatment is vital to stop this pest from taking hold.
Why Screwworm Threatens Farmers
Texas, America’s cattle capital, faces massive risks. A screwworm outbreak could kill livestock worth $1.8 billion at a time when beef prices are at an all-time high. The pest also attacks wildlife and pets, threatening ecosystems and rural life. Ranchers fear a return to the days when calves died in agony from infested wounds.
What’s Being Done to Stop Screwworm?
The USDA is fighting back. They’re spending $165 million to release sterile flies in Central America. A new Texas facility will produce millions more flies to halt the pest’s spread. However, it won’t be ready for years. For now, border checks are stricter, and ranchers are trained to spot infestations. These steps aim to protect our food supply and prevent economic disaster.
Can We Keep Screwworm Out?
The screwworm’s march north shows how fragile our defenses are. New genetic tools could help, but they’re not ready yet. Meanwhile, everyone—ranchers, pet owners, and travelers—must stay vigilant. Check wounds, report odd sores, and avoid risky areas. So, can America act fast enough to stop this flesh-eating invader before it’s too late?
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