No, while New World screwworm primarily affects livestock, it can infest almost any warm-blooded animal, including pets, wildlife, and, less commonly, humans and birds.
New World screwworm has been in the news lately, and there's a good deal of confusion about who and what it actually affects. The short answer is that it's mostly a livestock problem. But it’s not exclusively a livestock problem.
New World screwworm sounds like a worm, but that’s a misnomer. It’s a fly and its larvae burrow into the living tissue of open wounds. Any mammal with a wound can be at risk, not just cattle. It’s painful and, in animals, can be serious or even fatal if left untreated for a long time.
Livestock like cattle are at the biggest risk. However, it’s possible for the parasite to infest dogs, cats, wildlife, and, uncommonly, people and birds.
Screwworm was eradicated from the United States back in 1966 by releasing sterile males into the wild which cut off reproduction on a population level. But it re-emerged in Central America in 2023, spread through Mexico, and showed up in Texas and New Mexico in 2026. Federal and state agencies are responding with surveillance and renewed sterile-fly releases.
Currently, there are no reported locally acquired human cases in the United States. Health officials consider the public risk to be low and isolated to areas with active fly populations. However, taking basic precautions is still recommended. Keep all open wounds clean and covered, and thoroughly check your pets for any wounds containing maggots. If you notice anything unusual, contact your doctor or veterinarian.
This situation is changing quickly, so your most up-to-date resources will be the USDA (screwworm.gov), the CDC, and the Texas Department of State Health Services.
For screwworm specifically, your veterinarian, doctor, and those agencies are the right resources. This isn't something a yard treatment addresses. Where Mosquito Squad of Houston can help is with the everyday biting and nuisance insects around your property, mosquitoes, ticks, and flies, helping protect your yard with up to 90% reduction in mosquito activity on a recurring 21-day cycle.
