New World Screwworm in Texas: How to Protect Your Dog or Cat
Updated September 21, 2026
New World screwworm has recently become one of the most discussed animal-health topics in Texas. The name sounds frightening, but accurate information can help pet owners respond calmly and quickly.
The U.S. Department of Agriculture currently describes the overall risk to animals and people in the United States as very low. However, cases have been detected in animals in parts of Texas and New Mexico, so families should know what to watch for—especially when a pet has an open wound or has traveled through an affected area.
What Is New World Screwworm?
New World screwworm is caused by the larvae of a parasitic fly. Unlike the larvae of many flies that feed on dead tissue, screwworm larvae feed on the living tissue of warm-blooded animals. Dogs, cats, livestock, wildlife, and people can be affected.
The adult female fly lays eggs at the edge of a wound or, less commonly, near a natural body opening. When the eggs hatch, the larvae enter the tissue and can cause the wound to enlarge rapidly.
This is called myiasis. It requires prompt medical or veterinary attention.
Can Dogs and Cats Get Screwworm?
Yes. Any dog or cat with exposed tissue can potentially be affected where screwworm flies are circulating. A wound does not have to be large. Possible entry sites include:
Cuts, scrapes, punctures, and bite wounds
Surgical incisions
Hot spots or severely irritated skin
Tick or insect-bite sites that have been scratched open
Areas around the eyes, ears, nose, mouth, or genital region
A newborn animal’s healing umbilical area
Outdoor pets, animals with wounds, and pets that have recently visited an affected area may face greater exposure. Still, most pets in the United States remain at low risk.
Warning Signs Pet Owners Should Not Ignore
Check your pet carefully if a wound is not healing normally or suddenly becomes worse. Possible signs include:
A wound that enlarges, deepens, or continues to bleed
Unusual or foul-smelling drainage
Visible eggs or moving larvae in or around the wound
Flies repeatedly gathering around one area of the pet
Excessive licking, scratching, or biting at a wound
Pain, swelling, redness, or restlessness
Reduced appetite, weakness, fever, or unusual behavior
A screwworm infestation can progress quickly. Do not wait to see whether visible larvae disappear on their own.
What Should You Do If You Suspect Screwworm?
Contact a veterinarian immediately and keep your pet indoors, away from flies and other animals, while arranging care. Tell the veterinary team if your pet recently traveled to South Texas, New Mexico, Mexico, Central America, or another area with active cases.
Avoid pouring insecticide, bleach, alcohol, gasoline, essential oils, or other household products into the wound. These substances can damage tissue, cause poisoning, make examination more difficult, and delay appropriate treatment. Do not rely on removing only the larvae you can see; larvae may be deeper in the tissue.
Veterinary care may include careful wound examination, removal of larvae, thorough cleaning, pain control, treatment of damaged tissue or secondary infection, and follow-up wound care. Suspected cases may also need to be reported to animal-health authorities so the parasite can be identified and its spread monitored.
The FDA has authorized certain animal-drug options for New World screwworm under specific circumstances. Treatment should still be guided by a veterinarian because killing larvae does not replace wound cleaning, removal of remaining larvae, or treatment of tissue damage—and it may not prevent reinfestation.
How to Lower Your Pet’s Risk
Simple daily habits can make a meaningful difference:
Inspect your pet after outdoor activity. Look under the collar, between the toes, beneath the tail, around the ears, and anywhere your pet has been licking.
Have wounds evaluated early. Bite wounds and punctures may look small at the surface while hiding deeper damage.
Keep wounds clean and covered as directed. Follow your veterinarian’s instructions and prevent licking with an e-collar or recovery suit when recommended.
Keep pets indoors during wound healing. Limiting exposure to flies is especially important.
Keep the environment clean. Promptly remove waste, spoiled food, and other materials that attract flies.
Review travel plans. Before traveling with a pet to an affected region, check current USDA guidance and ask your veterinarian whether additional precautions are appropriate.
Monitor surgical incisions every day. Call if you notice opening, swelling, discharge, odor, increasing redness, or persistent licking.
Is Screwworm Contagious?
No. New World screwworm is not spread directly from one pet to another or from a pet to a person. Infestation occurs when a screwworm fly lays eggs on a wound or body opening. Even so, a suspected pet should be brought indoors to protect the wound from additional fly exposure and to allow prompt veterinary assessment.
Should McKinney Pet Owners Be Worried?
There is no reason to panic. The most useful response is awareness, regular wound checks, and timely veterinary care. The USDA maintains a current detection dashboard, and conditions can change. Pet owners should rely on updated government guidance instead of social-media rumors or graphic posts that lack location and context.
For families in McKinney, Frisco, Allen, Plano, and Fairview, the practical message is simple: check wounds daily, protect them from flies, and seek help quickly if a wound worsens or contains larvae.
When to Contact Petvise Animal Hospital
If your dog or cat has an open wound, an abnormal odor or discharge, visible larvae, increasing pain, or a wound that is getting worse instead of better, contact Petvise Animal Hospital promptly. Same-day evaluation may be appropriate because early treatment can limit tissue damage and discomfort.
Petvise Animal Hospital provides veterinary care for dogs and cats in McKinney and surrounding North Texas communities.
Call Petvise Animal Hospital or book an appointment online at www.petvisevet.com. If your pet is severely weak, collapsing, bleeding heavily, or having trouble breathing, seek emergency veterinary care immediately.
This article is for general education and is not a substitute for an examination or individualized veterinary advice.
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