New World Screw Worm and Your Pet
As you may have heard, a previously eradicated parasite called New World Screwworm (NWS) has recently been detected in Texas. Significant public health efforts are already in place to control this pest, but you may be wondering if you should be worried about your pets! Travis County has not been affected as of June 17, but that may change.
NWS can infect any warm-blooded animal through wounds. Humans and birds are at quite low risk, and reptiles are not at risk.
Luckily, there are safe and reliable medications that can prevent and treat NWS. The following medications have obtained an emergency or conditional approval by the FDA for treatment:
- Dogs: Nexgard, Nexgard Plus, Credelio, Credelio Quattro, nitenpyram
- Cats: Nexgard Combo, Credelio Cat, nitenpyram
- Exotic mammals, birds: F10 ointment, F10 barrier spray
FOR DOGS AND CATS:
We already recommend year-round parasite prevention for dogs and cats, and we carry the Nexgard product line at the clinic for this purpose. We also recognize that while only those few medications listed above have been specifically granted approval by the FDA for use during this outbreak, it is likely that other modern parasite medications in the same drug class as Credelio and Nexgard would be effective. Medications in the same drug class include Bravecto & Bravecto Plus, Simparica & Simparica Trio, and Revolution Plus. If your pet receives one of these preventive medications, it is reasonable to continue that medication.
Regarding nitenpyram (generic Capstar)- it’s important to note that this medication is a short-term treatment and cannot be used to prevent infection, only treatment after infection has occurred. We do not recommend relying on this medication to prevent infection in your dog or cat.
Additional steps you can take to ensure your pet is safe are to closely examine any wounds for signs of fly eggs, keep wounds clean if there are no signs of infestation, and notify us if you have any concerns about this in your pet. If there is concern for infection, we have targeted treatments at the clinic.
FOR SMALL MAMMALS AND BIRDS:
If your pet lives indoors, their risk of NWS is very low, but keeping watch for any wounds is necessary, and using F10 wound spray for prevention would be reasonable.
If your pet primarily lives outdoors, prevention with F10 wound spray and daily wound checks are recommended.
We will try to have F10 wound spray available in-clinic; however, we are running into issues with this product being out of stock. If you would like to purchase it, please call ahead to ensure availability. It is an over-the-counter product, which means a prescription is not needed.
If you’d like to read more, the Texas Tribune published a helpful article last week: https://www.texastribune.org/2026/06/11/screwworm-pets-what-to-know/
If you have further questions about New World Screwworm in relation to your pet, please don’t hesitate to reach out. As it stands, the outbreak is much more likely to affect wildlife and livestock than companion animals, but we are here to help!