FDA Issues Emergency Use Authorization to Treat Screwworm in Dogs

Lisa Selvaggio
by Lisa Selvaggio

On October 24, 2025, the U.S. Food and Drug Administration (FDA) released a statement regarding the use of Credelio for screwworm in dogs. By issuing an Emergency Use Authorization (EUA) for this medication, they are making a treatment available in the United States for dogs who are diagnosed with New World screwworm (NWS).  

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Credelio Receives Emergency Use Authorization


Credelio (lotilaner) is an antiparasitic drug that comes in the form of a chewable tablet, and it was FDA approved in 2018 to fight fleas and ticks on dogs. Now, experts believe that it may also be an effective treatment for NWS in puppies and adult dogs.


This is the first ever EUA issued for an animal drug. Also, Credelio is the first drug that the FDA has authorized for NWS treatment in companion animals. In the event that a veterinarian encounters a dog with NWS, they’ll be able to take action to treat it right away.  


There are potential side effects (e.g., neurologic reactions) that come with Credelio use, but it’s believed the benefits outweigh the risks, and this EUA allows experts to be proactive about treating any NWS cases that might occur in the country.


The Risk of New World Screwworm in Dogs


NWS is a parasite that infects animals, and it can infect humans too. The NWS fly lays its eggs in an open wound or break in the skin, and when the larvae hatch, they burrow into and feed on tissue.


So far, most of the dogs in the U.S. aren’t at a high risk of getting NWS. However, dogs who live near the border with Mexico, as well as those who travel to other countries where NWS is a threat, are considered at greater risk.


Consult Your Veterinarian to Determine What’s Best for Your Dog


Talk to your veterinarian about your dog’s risk of NWS, and about the pros and cons of using Credelio. If your canine companion needs this medication, you’ll have to get a prescription from your vet, and while your dog is taking this product, they should be closely monitored for side effects as well.


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Lisa Selvaggio
Lisa Selvaggio

Lisa Selvaggio is a freelance writer and editor, and our resident cats-pert, with certifications in pet nutrition and pet first aid. She enjoys producing content that helps people understand animals better so they can give their pets a safe and happy home.

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