A ranch horse in West Texas is the first horse in the United States to catch a flesh-eating bug. The bug is called the New World screwworm. State and federal workers found the pest in a cut on the horse's back leg. They found it on September 9. The horse lives on a working ranch in Presidio County. That is near the Texas-Mexico border.

This is a big deal for horse owners. Horses, cattle, goats, sheep, dogs and cats can all get this bug. So can people. Texas has been fighting this outbreak since June. Until now, no horse had caught it. Doctors say infected animals can be cured if the wound is treated fast.

Here is how the bug works. It is not really a worm. It is the young form of a fly. A mother fly lays eggs in a wound, or in an eye, or in soft wet skin. The eggs turn into small white worms called larvae. The larvae eat living flesh. The wound grows bigger fast. It can smell bad. More flies come to lay more eggs. If no one treats it, an animal can die in days.

The Texas Animal Health Commission acted fast. The state agency drew a new no-move zone. It covers parts of Presidio and Jeff Davis counties. Inside that zone, warm-blooded animals cannot leave without a state okay. A trained inspector has to check the animal first. The inspector writes a paper that says the animal got the right shots and creams. This rule covers horses, cows, goats, dogs and cats.

State records show 49 screwworm cases in the United States since June. Most hit cattle first, then a few dogs. As of this week, only two cases are still active. One is this horse near the border. The other is a dog in Crockett County, found August 31.

The main weapon against the bug sounds strange. The weapon is more flies. Workers raise millions of screwworm flies in a lab. Then they make the flies sterile, so they cannot have babies. Planes drop the sterile flies over Texas. Wild female flies mate with the sterile ones. No eggs hatch. Fewer new flies are born. Do that long enough, and the bug dies out. Texas beat the screwworm this same way back in the 1960s.

Right now, the country does not have enough sterile flies. Only 800 million had gone out by late August. The job needs many more. To help, a company called Flyttr is building a new fly plant. It sits on the East Side of San Antonio. The company says it can start making flies there within six months. The USDA is also building a bigger plant. That one is at Moore Air Base in Edinburg. It will not make flies until late 2027.

Money is at stake too. The USDA says the bug could cost Texas ranchers $732 million a year. It could cost the whole Texas economy $1.8 billion.

The U.S. Equestrian Federation runs horse shows across the country. The group is asking every horse owner to check their animals every day. "Check horses daily, keep wounds clean and covered as directed by your veterinarian, use veterinarian-recommended fly control products, and limit fly access with physical barriers such as fly masks, sheets, and clean stabling practices when appropriate," the group said in a statement.

This is an update to a story El Tejano has been following. El Tejano wrote about the risk of screwworm spreading through horses on September 10. You can read that story here: https://www.eltejanorgv.com/sterile-flies-from-edinburg-smuggled-horses-and-a-screwworm-now-inside-texas/

The outbreak started on June 3 with a calf in Zavala County. Since then, the bug has shown up on ranches and in homes. It has hit South and West Texas the hardest. Some counties have already been cleared. They are free of the no-move rules now. Others stay locked down for now. That includes the new zone around Presidio and Jeff Davis counties.

U.S. Agriculture Secretary Brooke Rollins said the fight is not over. "We're not out of the woods yet," Rollins said. She said officials are also watching for the bug near Arizona and New Mexico.

Vets and state workers say the best defense for now is simple. Look at your animals every day. Check every cut for worms, a bad smell, or drainage. Call a vet right away if something looks wrong. Early treatment can save an animal's life.