Texas vets warn pet owners about flesh-eating screwworm
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The New World screwworm (NWS) may sound like a livestock problem, but Texas veterinarians say pet owners should pay attention too.
Why it matters: Confirmed cases of the flesh-eating parasite are creeping closer to Bexar County.
The latest: Texas has confirmed 15 cases of NWS, all involving goats, cattle and sheep. A separate case confirmed in Lea County, New Mexico — which borders Texas — involved a dog.
- Cases have been confirmed in Zavala and Gillespie counties, neighboring Bexar County.
- City spokesperson Mia Garza-White tells Axios that San Antonio Animal Care Services (ACS) is not aware of any confirmed local cases of NWS.
Threat level: Female screwworm flies lay eggs in wounds and skin openings, including scratches, insect bites and surgical incisions. The larvae feed on living tissue, causing severe damage and, if left untreated, death.
Pet owners should watch for:
- Unusual swelling, discharge or a foul odor from a wound
- Excessive licking or signs of pain
- Loss of appetite or lethargy
If you suspect an infestation, seek veterinary care immediately. There are no effective home remedies.
What they're saying: Lori Teller, a veterinarian and executive director of the Texas Veterinary Medical Association, tells Axios any pet that spends time outdoors — whether in rural or urban areas — could be at risk.
- "Flies themselves do not discriminate between rural and urban communities," Teller says. "They go where the animals are."
Between the lines: Several flea and tick preventives prescribed for dogs and cats have received FDA authorization to treat NWS infestations, meaning pets already on those medications may have some protection.
Context: NWS was eradicated in the U.S. decades ago and largely contained in Panama. Since 2023, cases have spread northward, reaching U.S. soil this month.
State of play: The Department of Agriculture is deploying a $1.3 billion "New World Screwworm response."
- That includes setting up a $750 million Texas plant to produce and release 300 million sterile male screwworm flies every week.
Zoom in: Garza-White says ACS staff have been trained on NWS response protocols and the agency is prepared to take additional measures if needed.
The bottom line: Pet owners don't need to cancel hikes or dog park trips, but Teller says they should check wounds more carefully.
- Pets remain at greater risk from heatstroke, fleas and ticks than from screwworms, she says.
- "Vigilance, yes; panic, no," she says.