A flesh-eating parasite that hadn’t been seen in the US for decades is back, and pet owners are understandably alarmed. Here’s the honest version: the risk to most dogs and cats right now is low, but if you live in an affected area, knowing the warning signs matters a lot.

The parasite is the New World screwworm, and it returned to the country when the USDA confirmed larvae in the umbilical area of a calf in southern Texas on June 3, 2026. Cases so far have been detected in Texas and New Mexico.

What makes screwworm different from regular maggots

This is the part that makes people squeamish, and it’s important to understand. Ordinary maggots feed on dead tissue. New World screwworm larvae feed on living tissue. They burrow deeper into even a small wound as they eat, which is exactly why the infestations get serious fast.

Any warm-blooded animal can be affected, including dogs and cats. The larvae target wounds, so even a minor cut, a scratch, or a healing surgical site can become an entry point.

How worried should you actually be?

Not very, if you’re outside the affected states. Health officials have been clear that the overall risk to most US pet owners remains very low. A few things worth knowing to keep the panic in check:

  • Screwworm is not contagious pet-to-pet. Your dog can’t catch it from another dog.
  • It is not a food safety issue. The US food supply remains safe.
  • The current known cases are concentrated in Texas and New Mexico.

If you live in one of those states, or you’re traveling there with pets, awareness is more important because early treatment dramatically improves the outcome.

The warning signs to watch for

Because the larvae invade wounds, the guidance for pet owners comes down to watching any wound closely. Contact your veterinarian right away if you spot:

  • Maggots in or around a wound
  • Draining sores that won’t heal
  • A foul odor coming from a wound

Those are the red flags. When it comes to screwworm, waiting to “see if it clears up” is the wrong move. The larvae only dig deeper.

There’s now a treatment approved for pets

Here’s the genuinely good news. On June 11, 2026, the FDA issued an Emergency Use Authorization for generic nitenpyram tablets, the same active ingredient found in flea products like Capstar, to treat screwworm infestations in dogs, puppies, cats, and kittens.

It applies to animals that weigh at least two pounds and are at least four weeks old, and it’s the first generic animal drug authorized against the parasite. Nitenpyram works fast, killing most screwworm larvae within hours of the first dose.

That means if the worst happens, there’s an accessible, over-the-counter-style treatment that vets can reach for immediately.

Practical steps if you’re in an affected area

You don’t need to keep your pets inside forever. A few sensible habits go a long way:

  • Check your pets regularly for wounds, especially outdoor animals
  • Clean and monitor any cut, scratch, or surgical site
  • Keep an eye on the belly area and any spot your pet keeps licking
  • Call your vet at the first sign of maggots, draining, or odor

The bottom line

The New World screwworm is a nasty parasite with a genuinely alarming way of feeding, and its return to the US is a real story worth paying attention to. But for most pet owners, this is a “know the signs” situation, not a “panic” one. Watch wounds, act fast if something looks off, and know that a fast-acting treatment now exists.

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