Table of contents
Key Takeaways
- The New World screwworm has reached the United States for the first time in about 60 years, but for the average dog or cat the risk right now is low. As of mid-June 2026 there has been exactly one confirmed companion-animal case in the country (a single dog) and no cats, with nearly all detections in livestock concentrated in Texas and New Mexico.
- Screwworm does not spread casually from pet to pet. It needs a fly to lay eggs in an existing wound or moist opening, and it spreads mainly when infested animals are physically moved over long distances, which is why the official response focuses on inspecting and restricting animal movement out of affected areas.
- The danger lives almost entirely in cases that go unnoticed, so the practical job for pet owners is simple: learn the signs, check wounds to be sure they are healing, stay travel-aware, and call your vet if something looks off. FDA-authorized treatments for dogs and cats now work fast, and a case caught early is very manageable.
The coverage has leaned hard on the dramatic details, and to be fair, the biology is genuinely unsettling. But a few facts put it in proportion.
As of mid-June 2026, the United States has confirmed roughly a dozen screwworm detections since the first one on June 3, and nearly all of them have been in livestock like cattle and goats, concentrated in Texas and New Mexico. Among companion animals, exactly one dog has been confirmed in the entire country (a small-breed dog in Lea County, New Mexico), and so far no cats at all. Officials believe that single dog case was isolated, and it's being investigated partly because the dog may have traveled.
That last point is key to understanding your risk. Screwworm doesn't spread casually from pet to pet or drift through the neighborhood looking for victims. It spreads mainly when infested animals are physically moved over long distances, which is exactly why the response focuses on inspecting and restricting animal movement out of affected areas. A dog lying in your backyard in a state with no detections is in a very different situation than the headlines might suggest.
This is a real animal-health threat worth understanding. It is not, for most pet owners, an emergency.
What this thing actually is, and why it's still worth taking seriously
The New World screwworm is a parasitic fly. The adult looks a lot like a common housefly, and the adult isn't the problem. The problem is the larvae.
Most maggots you might find in a wound feed on dead, rotting tissue, which is unpleasant but essentially nature's cleanup crew. Screwworm larvae are different: they feed on living flesh. A female fly is drawn to an open wound or a moist opening, lays her eggs there, and within about a day the larvae hatch and begin burrowing into healthy tissue, like a screw twisting into wood. That's where the name comes from, and it's why an untreated case can turn a small wound into serious damage quickly.
So why stay calm if it's that nasty? Because the parasite has real limits. It needs an entry point, like a wound, a surgical site, or a moist opening, to get started. It can't infest healthy, intact skin. And critically, it's treatable. Over the past year the FDA has authorized a range of treatments for pets, including a fast-acting generic option for dogs and cats that kills most larvae within hours of the first dose. A case caught early is very manageable. The danger is almost entirely in cases that go unnoticed and untreated, which is exactly why knowing what to look for matters.
Your real risk, and what to look for
For most dogs and cats, especially outside Texas and New Mexico, the practical risk today is low. It's higher worth-paying-attention-to territory if you live in or near an area with confirmed cases, or if you travel with your pet across affected regions or back from Mexico.
Either way, the signs are easy to learn. With any wound or opening on your pet, watch for:
- A wound that isn't healing, or is actually getting bigger, deeper, or worse over a day or two instead of closing up.
- Visible larvae or eggs in or around a wound, or near body openings like the ears, eyes, nose, mouth, genitals, or a newborn's navel.
- Foul odor and drainage coming from a wound.
- Your pet fixating on a spot, licking, biting, or seeming bothered or uncomfortable in one area.
A couple of myth-busters that help keep things in perspective. Screwworm does not cause coughing or respiratory illness, so a cough is not a sign of it. And finding maggots in a wound does not mean your pet has screwworm. Ordinary fly strike from common flies is far more likely, and only a specialist can actually confirm screwworm. The takeaway isn't to assume the worst every time you see a wound. It's to not let a wound that's behaving strangely go unchecked.
How to keep your pet safe
The good news is that protecting your pet comes down to a few simple, low-effort habits.
- Keep an eye on wounds. Clean minor cuts, and check that they're healing the way they should. A wound that's closing up is doing what it's supposed to; one that's widening or smelling off is worth a closer look.
- Do a quick once-over now and then, especially after your pet has been outdoors, roughhousing, or recovering from surgery. A few seconds checking ears, face, and any sore spots is plenty.
- Be travel-aware. Avoid moving pets out of areas with confirmed cases, and be aware that some states now require a veterinary inspection certificate for animals coming from affected regions. If you've recently traveled with your pet through an affected area or from Mexico, keep an extra eye on any wounds for a while.
- If something looks off, call your vet. Don't panic, but do report. Screwworm is a reportable disease, so your vet may loop in animal health officials, but that's a routine part of the response, not a sign of disaster. Early treatment is highly effective, and the authorized options for dogs and cats work fast.
That's really the whole message: stay aware, learn the signs, check your pet's wounds, and reach out to your vet if something seems wrong. For the latest official information as the situation develops, Screwworm.gov is the place to check.
Frequently Asked Questions
An untreated infestation can cause serious damage and, in bad cases, can be fatal, which is why early detection matters so much. But that risk drops dramatically once a case is found and treated. The danger lives almost entirely in cases that go unnoticed, not in cases that get prompt care.
Not directly. You can't catch it from your dog or cat the way you'd catch a cold. Human cases do happen, but they're uncommon and occur the same way they do in animals, through a fly laying eggs in a wound or opening. If you ever notice a suspicious, non-healing lesion on yourself, especially after time in an affected area, see a doctor.
t's possible, but so far it's very rare. Across the whole country, only one dog and no cats have been confirmed in the current outbreak, and that single dog case is believed to be isolated. Any warm-blooded animal with an open wound can be a target, but the overall risk to a typical pet right now is low.
Probably not. Ordinary fly strike from common flies is much more likely, and those maggots feed on dead tissue rather than burrowing into healthy flesh. Only a specialist can actually confirm screwworm, so have your vet take a look rather than assuming the worst.