The Texas Animal Health Commission locked down parts of seven counties this month after New World screwworm cases spread across a widening stretch of the state's ranching heartland, a pest outbreak that now threatens cattle, goats, and other warm-blooded animals with a parasite the United States thought it had eradicated decades ago.
TAHC Executive Director Lewis Dinges on Tuesday, June 9, placed parts of Gillespie, Kerr, Kimble, La Salle, and Webb counties under animal movement restrictions. That order came just six days after the commission imposed the same quarantine on parts of Zavala and Uvalde counties on June 3, following the USDA's confirmation of the first U.S. case.
Six confirmed screwworm cases now sit inside Texas, USA Today reported. A seventh case, a dog living in Lea County, New Mexico, but first reported by a veterinarian in Andrews County, Texas, on June 7, puts the confirmed U.S. total at seven across two states. The speed of the spread, from a single confirmed case on June 3 to seven in barely a week, should alarm anyone who depends on Texas livestock for a living.
The restrictions are not suggestions. Under the TAHC quarantine order, no warm-blooded animal inside the designated zones may be moved outside the quarantine boundary without prior commission authorization. Owners and anyone else in possession or control of such animals must obtain permission and comply with every condition TAHC sets before transporting livestock or other animals beyond the line.
Before any animal leaves a quarantined area, it must be inspected and treated as TAHC requires, then issued a permit or certificate for movement by a TAHC representative. The rules extend beyond live animals. Hides, carcasses, and parts of any animal that could host the screwworm must also be inspected and treated before removal.
Violators face administrative penalties or criminal prosecution. That is not boilerplate. It is a measure of how seriously Texas treats the return of a parasite that inflicts real economic damage on ranchers and real suffering on animals.
The six Texas cases cluster in the state's southern and central ranch country. La Salle County and Zavala County each have two confirmed cases, all in domestic cattle. Gillespie County has one case in a domestic goat. Edwards County has one case in domestic cattle.
The geographic footprint is telling. La Salle and Webb counties sit along the border corridor. Zavala and Uvalde counties are just north. Gillespie, Kerr, and Kimble counties push the quarantine zone deeper into the Texas Hill Country, well north of the border and into some of the state's most productive ranching land.
That the quarantine area has already expanded twice in nine days, first on June 3, then again on June 9, tells ranchers and regulators alike that the outbreak is not yet contained.
On June 3, TAHC issued its initial quarantine order covering parts of Zavala and Uvalde counties after the USDA confirmed the first U.S. screwworm case. Four days later, on June 7, a veterinarian in Andrews County reported a case in a dog. The USDA classifies that case under Lea County, New Mexico, because the dog lives there, a jurisdictional detail that matters for federal tracking but does little to comfort Texans watching the map fill in.
By June 8, cases were confirmed in Gillespie and La Salle counties. The next day, Dinges expanded the quarantine to five additional county zones. And by June 11, when USA Today published its account, six Texas cases were on the books.
New World screwworm is not a nuisance pest. The fly lays its eggs in open wounds on warm-blooded animals. The larvae feed on living tissue. Left untreated, infestations can kill livestock. The United States spent decades and hundreds of millions of dollars on a sterile-insect program that eradicated the screwworm from the country by the 1980s. Its return, in multiple counties, across state lines, is a serious biosecurity event.
For ranchers in the quarantine zones, the immediate burden is operational. Every animal that needs to move requires inspection, treatment, and a TAHC-issued permit. That means time, cost, and uncertainty layered on top of an already difficult market for cattle producers. And the quarantine boundaries themselves remain somewhat opaque, the TAHC order covers "parts" of each county, but the exact geographic lines matter enormously to producers trying to plan shipments and sales.
Several gaps remain. The specific treatments TAHC requires before an animal can be moved have not been detailed publicly. The administrative penalty amounts and criminal charges that could apply to unauthorized movement are likewise unspecified in publicly available reporting. And while TAHC has published at least one quarantine order, the June 3 document covering Zavala and Uvalde counties, the exact wording and boundaries of the June 9 expansion have not been widely circulated.
Ranchers deserve clarity on all of those points. A quarantine backed by the threat of criminal prosecution ought to come with precise, publicly accessible maps and rules. The state owes that much to the people whose livelihoods depend on moving cattle.
New World screwworm has long been endemic in parts of Mexico and Central America. The U.S. eradication program worked precisely because it maintained a biological buffer zone south of the border, releasing sterile flies to suppress the wild population before it could migrate north. That buffer has evidently failed, or at least been breached.
The concentration of early cases in border-adjacent counties like La Salle, Webb, Zavala, and Uvalde is not coincidental. It tracks the corridors through which animals, domestic and wild, cross between Mexico and Texas. Whether the screwworm arrived on migrating wildlife, on livestock moved across the border, or through some other pathway, the geographic pattern points south.
This is, at bottom, a border-security story as much as an agricultural one. A nation that cannot maintain a biological barrier against a known livestock parasite is a nation that has let its guard down at the line that matters most.
If the case count keeps climbing, expect the quarantine zones to expand again. TAHC has shown it will act quickly, two rounds of restrictions in nine days, but speed alone does not equal containment. The federal government, through USDA, will need to coordinate sterile-fly releases and surveillance on a scale that matches the threat. Texas ranchers, meanwhile, will bear the cost of compliance while waiting for answers about how the screwworm got here and how long the restrictions will last.
When a pest the country spent a generation eliminating shows up again in seven counties across two states in barely a week, the question is not whether the response was fast enough. The question is what broke down to let it happen in the first place.
