World 1,209 views on YouTube
America Killed This Fly In 1966. It's Back In Texas.
A New World screwworm infestation has been confirmed in a working ranch horse in Presidio County, Texas — the first horse in this outbreak. The Texas Animal Health Commission found it this week; a federal laboratory confirmed it.
The screwworm is a fly, and what makes it different from every other fly is that its larvae feed on living flesh rather than dead.
But the arrival is not really the story, because it already arrived. The first US animal case in this outbreak was a three-week-old calf in Zavala County on 3 June 2026.
The story is the wall. America eradicated this fly in 1966 by releasing sterile males until the population could not breed — one of the most successful pest programmes ever run — and then held the barrier at Panama for decades. In 2023 that barrier broke, and cases went from roughly 25 to 6,500. It reached southern Mexico in late 2024, Veracruz by July 2025, and came within 70 miles of the US border by September 2025.
When Texas last had an outbreak, in 1976, it cost producers the equivalent of $732 million in today's money.
The half that rarely gets reported: the system is fighting. More than a billion sterile flies have been released since February, and restrictions were lifted in five Texas counties the same week this horse was found.
There are no locally acquired human cases in the United States.
The reporting
Verified 2026-09-11 against USDA APHIS, the Texas Animal Health Commission, CDC, CRS, Reuters, The Horse, USEF/EDCC and Texas Public Radio.
References
Reporting drawn from USDA APHIS · Texas Animal Health Commission · Reuters · CRS · CIDRAP · CDC · The Horse
What the reel says
Narration as scripted and voiced.
A parasite the United States wiped out sixty years ago has turned up in a Texas horse
It is called the New World screw worm. It is a fly, and its larvae feed on living flesh rather than dead
The case is a working ranch horse in Presidio County, an infestation in a hind limb found this week by the Texas Animal Health Commission and confirmed in a federal laboratory.
It is the first horse in this outbreak. It is not the first animal. That was a three-week-old calf in Zavala County on the 3rd of June
Which is why the arrival is not really the story. The story is the wall that used to stop it
America eradicated this fly in 1966 by releasing sterile males until the population could not breed. The barrier was then held in Panama for decades
In 2023, that barrier broke and cases went from about twenty-five to six thousand five hundred. It reached southern Mexico in late 2024, Veracruz by July, and came within seventy miles of the border by September of last year
When Texas last had an outbreak in 1976, it cost producers the equivalent of seven hundred and thirty-two million dollars in today's money
The other half of the story is that the system is fighting. More than a billion sterile flies have been released since February, and restrictions were lifted in five counties the same week this horse was found
A wall built out of sterile insects held for 60 years. It took three years to walk 1,500 miles around it
All footage is licensed stock. No parasite or wound imagery.
