Screwworm Has Texas Pet Transports on Hold. Here's What to Watch for on Your Own Dog.

By mChip.org Staff Last updated August 20, 2026

Texas shelters have paused out-of-state adoptions after the first New World screwworm outbreak there in 60 years. Two of the confirmed U.S. cases were dogs. Here's what the parasite does, what a wound looks like, and what owners outside the affected zone actually need to do.

Rescue groups across Texas have stopped sending animals out of state, and the reason is a fly.

The New World screwworm — a parasite the U.S. eradicated decades ago — crossed back over the Mexican border this year. The first confirmed U.S. animal case landed on June 3, 2026, and it's the first outbreak Texas has seen in about 60 years. Two of the confirmed cases have been pet dogs.

That's set off a scramble that has very little to do with most people's dogs and everything to do with the ones still sitting in shelters.

What actually changed this week

Texas shelters have paused most out-of-state adoptions and transports. According to reporting on the Houston Humane Society and Gulf Coast Humane Society, 44 states have restricted animal imports from affected areas of Texas, and Florida has banned them outright. Most states now want a veterinarian to certify an animal is screwworm-free before it crosses the line, and some have shortened how long that certificate stays valid — from 30 days down to as little as three.

Three days is not much of a window when you're coordinating a transport van to Ohio.

The scale matters here. Texas moved roughly 89,000 dogs and 53,000 cats out of state in 2025, mostly to the Northeast and Great Lakes, where shelters have space and Texas doesn't. That pipeline is now mostly closed, which means crowded kennels, longer stays, and more stressed animals — and stressed animals, as Houston Humane Society's Aaron Grady noted, are harder to place.

On the livestock side, southern ports of entry have been closed to cattle trade, with a phased reopening planned to begin August 24 at Douglas, Arizona.

What a screwworm actually does

It isn't a worm. It's the larval stage of a blowfly, and unlike most maggots — which feed on dead tissue — screwworm larvae burrow into living flesh.

A female fly lays her eggs at the edge of a wound or at a moist opening: nose, ears, mouth, eyes, navel, genitals. The AKC Canine Health Foundation notes that the entry point can be trivially small — "a tick bite, minor scratch, or needle-stick site." Eggs hatch in 12 to 24 hours. The larvae then feed downward into healthy tissue, and the wound gets bigger instead of closing.

The signs

The CDC's guidance and the AKC's line up on what to look for:

A wound that's getting larger rather than healing
Bleeding from a wound that shouldn't be bleeding
A distinctly foul smell
Visible larvae, or movement, in a wound or in the nose, mouth, eyes, ears, or genitals
Obvious pain around the site

If you see larvae, that's a call-your-vet-today situation, not a wait-and-see one. Don't try to dig them out yourself — the larvae anchor themselves, and pulling at them can leave pieces behind and make the infestation worse.

How worried should you be?

For most pets in most of the country, not very. The CDC's assessment is that "the current risk to the public and animals in the U.S. is very low," and confirmed detections have been concentrated in southern Texas and southeastern New Mexico.

The animals at real risk are the ones with open wounds in or near an active zone: free-roaming dogs, strays, recently rescued animals, and pets that have traveled to or from affected areas of Mexico. Dogs entering the U.S. from Mexico now require inspection by an authorized veterinarian and certification that they're screwworm-free.

One thing that isn't a concern: screwworms don't infest meat, produce, or other food. Your dog's dinner is fine.

What's worth doing anyway

None of this requires a panic response, but a few habits are cheap:

Look your dog over after outdoor time. Not a full inspection — just run your hands over them. You're checking for cuts, hot spots, torn nails, ear scratches, anything raw.

Clean and cover small wounds instead of letting them air out. An open wound is the invitation.

Keep parasite prevention current. Tick bites and the scratching they cause create exactly the kind of broken skin that starts this. Refill before you run out rather than after.

Be extra attentive to a new rescue. Animals coming out of a stray situation are the most likely to arrive with a wound nobody's seen yet.

Call your vet about anything that smells wrong. Odor is the sign owners tend to notice first and dismiss fastest.

Treatment exists. The FDA has issued emergency use authorizations for several drugs to treat New World screwworm in dogs and cats, including an over-the-counter generic — but these are treatments a veterinarian should direct, not something to start on your own based on a wound you're unsure about.

If you were thinking about adopting

The transport freeze is squeezing Texas shelters hard right now, and the two things that help most are local: fostering, so kennels open up, and adopting in-state, which no restriction touches. Neither requires a certificate or a van.

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