A parasite eradicated decades ago has resurfaced in the United States, raising alarms among veterinarians and pet owners. Learn the key symptoms to protect your animals and act before it becomes serious.
The United States Department of Agriculture (USDA) has issued alerts after confirming the reemergence of the New World screwworm, a parasite that had been eradicated from the country in the 1960s. So far, the June 2026 outbreak has already affected livestock in Texas and a dog in New Mexico, causing concern in both the agricultural sector and among pet owners.
This parasite, recently detected moving northward from Central America, poses a serious risk. Early detection is therefore critical.
What is the screwworm, and why is it so dangerous?
The screwworm is actually the larva of a fly species. The cycle begins when the adult fly lays its eggs directly on open wounds of warm-blooded animals (including dogs, cats, livestock, and even, in very rare cases, humans).
Unlike other larvae, these have a lethal characteristic: they feed on living, healthy tissue. Once they hatch, they burrow into the animal’s skin, multiplying and worsening the wound at an accelerated rate. If not treated in time, secondary infections and tissue damage can be fatal.
Warning signs: How to detect screwworm in your pet
<Health authorities recommend conducting daily inspections of your pets, especially if they have been outdoors. Pay close attention to any cuts, scrapes, or exposed wounds.
Seek veterinary care immediately if you notice any of these symptoms in your pet:
- Non-healing wounds: Lesions that, instead of healing, appear to worsen or grow larger.
- Foul odor: An unpleasant or unusual smell coming from the wound.
- Visible presence of larvae: Worms moving inside or around the skin lesion.
- Redness and swelling: Areas of the skin that appear abnormally red or swollen.
- Behavioral changes: If your pet seems lethargic, agitated, or excessively licks a specific area of its body.
What to do if you suspect an infestation
If you detect any of these signs or see larvae on your pet, do not attempt to treat it at home.
- Seek urgent veterinary care: A professional must take samples, safely clean the damaged tissue, and apply specific antiparasitic treatments to stop the infection.
- Report the case: Since this is a monitored pest, veterinarians and pet owners can contact local and animal health authorities to report the suspected case and prevent the outbreak from spreading.
Key prevention measures
To protect your animals, follow these recommendations from the USDA and animal health commissions:
- Constant supervision: Check your pet daily for hidden wounds under its fur.
- Immediate wound care: Keep any cut, no matter how small, clean and covered.
- Travel precautions: Avoid moving animals with open wounds to or from areas where cases have been reported (such as Texas and New Mexico).
The risk to humans is low, but health authorities recommend caution in affected areas, especially if you have exposed wounds. The key to stopping this parasite, both at home and nationally, is constant vigilance.
