A trending topic of concern, especially for cattle and other livestock ranchers, is the New World Screwworm cases popping up over the last few weeks in New Mexico and Texas. As more information has been released, pet owners have been asking, “can this affect my dog or cat?” and the answer is yes.
How to protect your pet from the New World screwworm: Part of the treatment for animals infested with this parasite involves a class of drugs called Isoxazolines. If you keep your pet on monthly flea and tick preventative products like Simparica Trio or Bravecto, you’re already protecting them. If you’re not, consider signing up for Med Fetch and receive a free dose of Simparica Trio, plus a monthly dose delivered to your door.
How to tell if your pet has a new world screwworm: If you’ve noticed rice-like parasites (maggots) on open wounds or mucosal areas of your pet's body, veterinary care is urgently needed. Unlike regular fly maggots that consume dying tissue, the new world screwworm feeds on healthy tissue. The fly typically lays its eggs in open wounds (even small scratches), and when the eggs develop into larvae, they start feeding on the tissue around them. If you notice an open wound on your pet, seek veterinary care, keep them indoors to heal, and keep the area clean and dry. An official diagnosis of the new world screwworm takes 7-10 days after lab submission. If your dog or cat has been around cattle or has had known exposure to areas where this parasite is currently present, please disclose this to your veterinarian.
Your veterinarian is prepared to treat this condition: While media-fueled and absolutely a public health concern, we are prepared. We urge pet parents to be alert, but not alarmed, to monitor your pets for any abnormalities, and to do what you already would: communicate with your veterinarian if you are concerned about your pet.
As of June 26th, there have been 31 confirmed domestic cases in Texas in the following counties: Zavala, La Salle, Gillespie, Tom Green, Pecos, Crockett, Terrell, Sutton, Edwards, Medina, Uvalde, and Jim Hogg. The first and only case in Lea County, New Mexico, was a dog diagnosed in Texas (who lives in New Mexico) and it is now inactive. View current screwworm case status.
For additional information, you can visit sewwormnm.org, the USDA’s Department of Agriculture website, or give us a call at 806-355-9443
Publication date: 07/03/2026 | Swann Animal Clinic