Heads Up: New World Screwworm (NWS) in Companion Animals aka Pets

7:00 PM · June 26, 2026

Excerpt American Veterinary Medical Association avma.org

This guidance is intended to help veterinary teams recognize and respond effectively when a companion animal patient presents with wounds, larvae, or clinical signs suggestive of New World screwworm (NWS) myiasis (infestation) in a geographic area in which NWS flies have been identified or when animals have recently traveled from such areas. The information provided applies to any companion animal observed to have:

Larvae in a wound
Rapidly progressive wound enlargement
Deep, painful, draining wounds
Suspicious myiasis, especially involving living tissue
Recent history of travel or importation from an NWS endemic area

This guidance does not supersede directions issued by state animal health officials or U.S. Department of Agriculture (USDA) area veterinarians in charge or other federal animal health officials.

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Author Commentary

Beege Welborn Jun 26, 2026 7:00 PM ET

Lots to know here, and this is what I got in an email from the AVMA:

As new cases of New World screwworm (NWS) continue to be reported in Texas and one in New Mexico, the American Veterinary Medical Association (AVMA) is urging pet owners to protect their animals from this potentially deadly flesh-eating parasite.
Here is what every pet owner should know right now:
Dogs and cats are at risk. NWS is a parasitic fly whose larvae infest open wounds of warm-blooded animals, including household pets. Animals that are newly born, have open wounds, or have recently undergone surgery or medical procedures are especially vulnerable.
Know the warning signs. Pet owners should check their animals regularly for draining or enlarging wounds, maggots or egg masses, signs of discomfort, or lesions in body openings such as the nose, ears, genitalia, or umbilical area. If you notice any of these signs, contact your veterinarian immediately. Don’t try to remove the larvae from the wound yourself.
NWS is treatable, and several treatments are available. The FDA has authorized several treatments for NWS in dogs and cats. Treatment is time-sensitive, so don’t delay contacting your veterinarian if you suspect an infestation.
Travel precautions are in effect. All dogs and cats — including U.S.-origin dogs returning from Mexico — must meet USDA APHIS requirements for screwworm freedom certification upon re-entry into the United States. Pet owners planning travel to Mexico should consult their veterinarian in advance. Certain medical documents are required for travel.
The AVMA is working closely with the USDA, FDA and CDC to track this rapidly evolving situation and is available to provide expert veterinary perspectives.