gilbert examYou may have seen recent news stories about New World Screwworm, a type of fly whose larvae can invade open wounds in animals. While this is a serious disease where it occurs, the risk to pets in North Carolina remains very low. (Read more about it here.) Nevertheless, New World Screwworm (NWS) continues to be an evolving animal‑health concern in the United States. Since the first confirmed U.S. case on June 3, 2026, additional cases have been identified over time. As the situation develops, veterinarians nationwide (and here at Town N Country) are working to stay informed and prepared to protect pets.

Zoetis has announced that the Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for Simparica Trio® (sarolaner, moxidectin, and pyrantel chewable tablets) for the treatment of infestations caused by New World Screwworm (Cochliomyia hominivorax) larvae (myiasis) in dogs and puppies.This is Good News for You. Based on the available data, the FDA has determined it is reasonable to believe Simparica Trio® may be effective for treating NWS larval infestations. Simparica Trio® is not FDA‑approved for treating New World Screwworm. The EUA allows veterinarians to use Simparica Trio® for NWS while the emergency declaration is in force. Note that the authorization is temporary.

The FDA has also released a Freedom of Information (FOI) Summary outlining the data supporting the EUA. Both documents are available through the FDA’s EUA resource page.

What Simparica Trio® Is Approved For:
Outside of the EUA, Simparica Trio® remains fully approved for the things it has always been used for, including:

  • Prevention of heartworm disease
  • Treatment and control of roundworm and hookworm
  • Killing adult fleas and preventing flea infestations
  • Prevention of tapeworm infections
  • Treatment and control of multiple tick species
  • Prevention of Lyme disease

We’re Watching the Situation. We are closely monitoring updates from the FDA, USDA, and other veterinary infectious‑disease experts. If your pet has a wound, a non‑healing sore, or any signs of maggot infestation, you need to call us right away.

If you have questions about parasite prevention, wound care, or the EUA for Simparica Trio®, please contact us. We are here to help you navigate this evolving situation and – as always – to keep your pets safe.