If you're driving to Panama — or just crossing into Mexico with your dog for any reason — there's a new document you need that most people don't know about yet. Mexico's agricultural authority SENASICA quietly rolled out this requirement on August 3, 2026, and it applies to every dog crossing from the United States.
What is a New World Screwworm certificate?
The New World Screwworm (Cochliomyia hominivorax) is a parasitic fly whose larvae burrow into the living flesh of warm-blooded animals. Mexico eradicated it decades ago but detected renewed pressure near its northern border — and is now requiring proof that dogs from the US aren't carrying it across.
The certificate itself is a short inspection form completed by a USDA-accredited veterinarian. The vet visually examines your dog for any open wounds, skin lesions, or signs of larvae infestation, then signs off that the animal is clear. It's not a full health certificate — it's a targeted inspection for this one issue.
What you need and when
- Who issues it: a USDA-accredited veterinarian. Any vet who is USDA-accredited can issue this — it does not need to go through a USDA APHIS office for endorsement.
- Timing: must be issued within 5 days of your border crossing. Book your vet appointment accordingly.
- Who needs it: dogs crossing from the US into Mexico. Cats crossing from the US are still inspection-only at the border.
- Breed or size restrictions: none — this applies to all dogs regardless of breed or size.
How this affects the drive to Panama
The Pan-American Highway drive goes US → Mexico → Guatemala → El Salvador → Honduras → Nicaragua → Costa Rica → Panama. Mexico is the first major crossing, and it's now where your dog requires the most recent document on the entire route. You cannot cross Mexico without the NWS certificate — schedule the vet appointment no more than 5 days before your planned entry date.
What about flying?
If you're flying your dog to Panama and have a layover or connecting flight through a Mexican airport, check whether your itinerary technically constitutes an entry into Mexico. A direct US–Panama flight with no Mexican stop is unaffected. Any route that clears Mexican customs — even briefly — likely triggers this requirement. When in doubt, ask your airline.
Finding a USDA-accredited vet
Use the USDA APHIS accredited vet locator to find one near you. Search by state and city — accredited vets are more common than most people expect. Call ahead and confirm they are familiar with the NWS inspection form specifically, since it became required less than two months ago.
Written by Jon Flink, who moved to Boquete, Panama with his own dogs and runs the Pets to Panama™ community.