Texas Is Flooding Inside the Screwworm Zone, and a Veterinary Emergency Team Just Deployed Into Both

The Texas A&M Veterinary Emergency Team deployed Friday morning into Central Texas, where days of heavy rain have produced catastrophic flooding across the Hill Country and communities west of San Antonio. Evacuations, road closures and high water rescues are ongoing.The team went in as a state resource with a defined initial mission, providing veterinary care for Texas A&M Task Force and federal working dogs. They expect that mission to widen as communities with severe home flooding identify needs and emergency animal sheltering becomes necessary. So far this reads like a flood story, and most coverage will leave it there. It is not the whole story.

The detail that should stop a veterinary reader cold

Part of the flooded region sits inside a designated New World screwworm infested zone.

The team expects to keep working with the Texas Animal Health Commission to screen for screwworm and advice on it as sheltering operations stand up, alongside caring for companion animals and livestock affected by the water. Consider what a flood does inside a zone under active movement restriction, and why an emergency response veterinarian would be thinking about a parasite while the water is still up. Floods produce exactly what a screwworm fly is looking for, in exactly the places animals are about to be gathered together. Flooding produces wounded animals. Lacerations from debris, fence injuries, foot and limb trauma, macerated skin from prolonged immersion. New World screwworm flies lay eggs in open wounds and in the soft tissue of natural body openings on living, warm blooded animals.

Flooding also displaces animals, which is the second problem. Livestock go through downed fences. Wildlife moves. Companion animals are separated from owners and end up in emergency shelters. Every one of those movements is the kind of movement that quarantine zones exist to control, and floodwater does not check permits.

And emergency sheltering concentrates animals, some of them wounded, some from different premises, in temporary facilities with limited capacity for individual inspection. That is the setting in which screening protocols stop being paperwork and start being the whole job.

Why screwworm is a live emergency in Texas right now

On 3 June 2026, USDA confirmed New World screwworm in a three week old calf in Zavala County, with larvae identified in the umbilical area. It was the first detection in Texas since the parasite's northward progression from Central America was observed in 2023. An infested zone was established around the detection, with quarantines, movement controls and surveillance, and response has included expanded trapping and targeted release of sterile flies on top of the millions already being released aerially each week.

It did not stay at one case. By mid July, federal officials had confirmed more than 40 infestations, nearly all in Texas, with the geography widening rather than tightening. Detection counts have been moving weekly, so treat any number you read, including this one, as a snapshot.The reason this matters so much in Texas specifically is structural. The state carries one of the largest livestock industries in the country, enormous rangeland, and a very large wildlife population, particularly white tailed deer. If screwworm reestablishes, it has somewhere to live.

What screwworm actually looks like, and what to do

Worth knowing cold, whether or not you practice in Texas, because the geography of this problem is not finished moving.

New World screwworm is not a worm. It is the larval stage of the fly Cochliomyia hominivorax. The distinction that matters clinically is what the larvae eat. Ordinary maggots feed on dead and decaying tissue, which is why maggot debridement is a therapy. Screwworm larvae feed on living tissue, burrowing into healthy flesh and enlarging the wound as they go, which is why an untreated infestation progresses rather than resolves.

Suspicion should rise around any open wound in an at risk area, and particularly around wounds that are predictable and recent. Umbilical stumps in newborns, castration and branding sites, dehorning wounds, tick and insect bites that have been worried open, surgical incisions. Animals may be irritated or depressed, may separate from the group, and the wound itself may enlarge, discharge, or smell wrong.

If you suspect New World screwworm, do not move the animal. Contact the Texas Animal Health Commission immediately. The 24 hour veterinary on call line is 1-800-550-8242, and suspect or confirmed cases must be reported within 24 hours. Current guidance is at screwworm.gov.

Producers in affected regions are being advised to inspect animals frequently and to keep open wounds clean and covered, which is ordinary husbandry advice carrying an extraordinary amount of weight at the moment.

What to watch

Two things over the coming weeks. Whether the mission expands from working dog care into community animal sheltering, which is the signal that displacement has outrun local capacity. And whether any screwworm detections emerge from the flooded counties, which would turn a difficult response into a considerably harder one, because disease control and disaster response pull in opposite directions. Disasters scatter and concentrate animals. Quarantine depends on knowing where animals are and keeping them there.

For the moment, the useful thing most veterinary professionals can do is unglamorous. Know what screwworm looks like, know the reporting number, and if you are anywhere the geography could reach, start talking to clients about keeping wounds clean and covered before you need to.