06/12/2026
You’ve likely heard that the New World Screwworm (NWS) has been detected in cows in Texas, and recently, a dog in New Mexico. Here is what you need to know about NWS to keep your animals—and everyone else in your household—safe.
NWS is the larval stage of a fly that feeds on the living tissue of warm-blooded animals. The pest can infest many species of mammals and birds, including cats, dogs, and, in rare cases, humans. NWS is not contagious like a cold or the flu. It can only be spread by female flies laying eggs.
What should you look for?
Regularly check your animals for wounds or sores, even minor ones, which can serve as infestation sites. If you find a wound on your animal, keep it covered. But watch for:
• Swelling, discharge, or changes in the skin around a wound, even if you don’t see larvae.
• Continual licking or chewing of the same spot.
• Foul odor. Infested wounds are described as having a “putrid” smell.
• Changes in your animal’s appetite or activity levels.
If you see signs of an infestation in your animal:
• Isolate your animal immediately. If you have other animals, check them for signs of infestation.
• Contact a licensed veterinarian. Veterinarians are trained to examine wounds and provide appropriate treatment.
• Do not attempt to remove larvae or treat the condition yourself. Home treatment can lead to severe complications.
Federal and state authorities, including New Mexican state agencies, are working to halt the spread of NWS, and emphasize there is "no need to panic." While an untreated infestation can be potentially life-threatening, the condition is highly treatable when detected early. Staying alert can help keep you and your animals safe.
