Talk to your vet. This article reports what has been published and is not veterinary advice. Every dog is different, and guidance varies by country. If any of this might apply to your dog, speak to your own vet before changing anything about their food, medication or care.
If you are taking your dog into Mexico from the United States, the paperwork changed on 3 August 2026. Dogs now need an official USDA APHIS screwworm inspection certificate, signed by a USDA-accredited vet within five days of arrival. Cats are exempt. Pet birds need a separate addendum.
Behind that paperwork is a parasite that returned to the United States last year for the first time in roughly six decades. But the part of this story that matters most to a fluffy dog owner is not the form. It is a skin check that is genuinely harder to do on a thick coat.
What changed, and where it applies
The new Mexican requirement covers dogs arriving from the US. A USDA-accredited vet examines the dog for evidence of larval infestation, looking specifically at open wounds, tick bites, umbilical scars and mucous membranes, and issues the certificate within five days of arrival. It does not need separate APHIS endorsement.
Travelling the other way, dogs entering the United States from a screwworm-positive country need certification that they were examined within five days of travel and are free of larvae, or were treated and cleared beforehand. Several US states have also added their own rules for moving animals out of affected areas, typically a veterinary inspection certificate issued within five to seven days and, in some states, an entry permit requested in advance.
Which country does this affect? These are United States and Mexican rules. According to the American Kennel Club, 41 cases had been confirmed in southwest Texas and New Mexico as of 20 July 2026, the first US cases in about 60 years. If you are outside the Americas, none of this paperwork applies to you, but the coat check below still does.
Why this lands differently on a fluffy dog
The screwworm fly lays its eggs in open wounds, and a wound here can mean something very small: a tick bite, a nick from clippers, a scratch from a bramble, or the umbilical area on a newborn puppy.
On a short-coated dog you would simply see it. On a Samoyed, Chow Chow, Pomeranian, Bichon or a full-coated Shih Tzu, you will not see any of those things unless you deliberately part the coat and look at skin. A dense double coat is very good at hiding exactly the kind of small injury this parasite looks for, which is also why skin problems after grooming so often go unnoticed for days.
What to check, and where
Run your hands over the skin, not the coat, and part the hair anywhere you feel a lump, a scab or heat. Pay particular attention to:
- Anywhere recently clipped or scissored, where a small nick is easy to miss
- Ear margins and the folds behind the ears
- Under a collar or harness, where rubbing is common
- The belly, and the umbilical area on young puppies
- Between the toes and around the pads
The signs reported by veterinary and public health sources are maggots or visible movement in a wound, a foul or decaying smell, restlessness, head shaking, and a dog fixating on licking or chewing one particular spot. All of them advise immediate veterinary attention rather than home treatment.
Prevention that is already in most medicine cabinets
The USDA has said that oral and topical flea and tick preventatives containing afoxolaner, lotilaner or sarolaner actively prevent and treat screwworm larval infestations in pets. These are prescription products in most countries, so this is a conversation with your own vet rather than something to buy on the strength of a news story. If your dog is already on a year-round preventative, it is worth checking which ingredient it uses.
If you are travelling with your dog
Build in more time than you think. The examination has to fall inside a five-day window before arrival, and where government stamping is required it can take two to three business days on top. That is a tight sequence to arrange in a holiday week. Our guide to travelling with a fluffy dog covers the rest of the preparation, but the certificate is the part with a deadline attached.
The wider takeaway is a habit rather than a panic: on a thick-coated dog, a weekly hands-on skin check finds small wounds long before anything else does. That is useful in Texas this summer, and it is useful everywhere else for entirely ordinary reasons.
References
- Emerging Issue: New World Screwworm – Impacts on Health, Interstate Travel with Dogs — American Kennel Club, 2026-07-20
- Updated Mexico Pet Export Requirements for 2026 Explained — Kruiz
- What to know about protecting pets from the New World screwworm fly — The Washington Post, 2026-07-08
- How to protect your pets from the New World screwworm fly — PBS NewsHour
- How to protect outdoor pets from New World screwworm — CIDRAP, University of Minnesota