A parasite that was once eradicated from the United States is making its way back into the country, and pet owners should know what to watch for. New World Screwworm is a type of fly whose larvae, or maggots, feed on the living tissue of warm-blooded animals.

While the current U.S. cases remain limited to Texas and New Mexico, the situation can change, making awareness important for pet owners in Queen Creek and throughout the East Valley.

What Is New World Screwworm?

New World Screwworm is a specific species of fly whose larvae can infest wounds and other vulnerable areas on an animal. Unlike ordinary maggots that typically feed on dead tissue, screwworm larvae consume living flesh. Any warm-blooded mammal can potentially be affected. Livestock are particularly vulnerable, especially newborn animals, but dogs, cats, wildlife and even humans can become hosts.

The larvae can infest wounds as well as areas such as the eyes and reproductive organs. A small cut or injury that would normally heal without much trouble can become a serious, potentially fatal illness if screwworm larvae are present.

Why Is Screwworm Back in the News?

New World Screwworm was previously a major problem in the United States. From the 1930s through the 1960s, the parasite was present in the country until an innovative eradication program successfully eliminated it from the U.S.

The program used the Sterile Insect Technique, which involves releasing sterile male flies into affected areas. Female screwworm flies generally mate only once, so when they mate with a sterile male, they cannot produce viable offspring. Over time, this dramatically reduces the fly population.

The program has continued at maintenance levels, but New World Screwworm has recently been moving north through Mexico. The first recent cases in the United States were reported in 2026, with detections currently limited to Texas and New Mexico.

That makes this an important issue to watch, particularly for people who travel with their pets.

What Does This Mean for Arizona Pet Owners?

For families in Queen Creek, Gilbert, Chandler, Mesa and throughout the East Valley, there is no reason to panic. However, Arizona’s proximity to Mexico makes pet travel an important consideration.

Mexico now requires dogs traveling from the United States to have documentation related to New World screwworm. The United States also has requirements for dogs entering the country from Mexico.

Travel requirements can change as the situation develops, so if you’re planning to cross the border with your dog, check the latest USDA APHIS pet-travel requirements before your trip. Don’t rely on information from a previous trip, as the requirements may have changed.

What Should Pet Owners Look For?

The most important thing you can do is pay attention to your pet’s wounds.

Contact your veterinarian if you notice a wound that is:

• Becoming increasingly painful
• Producing a strong or unusual odor
• Getting larger or worse instead of healing
• Producing unusual discharge
• Attracting flies
• Not healing normally

A screwworm infestation isn’t always obvious at first, so any wound that seems unusual or is deteriorating rather than improving deserves veterinary attention. New World Screwworm can turn a small wound into a serious medical emergency, so early treatment is important.

How Can You Protect Your Pet?

The best approach is to prevent flies from gaining access to wounds and to maintain good parasite prevention. If your dog or cat has a wound, keep it properly cleaned and covered according to your veterinarian’s instructions. Regularly check your pet for cuts, scratches, bites or other breaks in the skin, particularly after spending time outdoors or traveling.

It’s also important to talk with your veterinarian about appropriate oral flea, tick and parasite prevention. Certain veterinary medications have been specifically authorized for the treatment of New World Screwworm in dogs and cats, but the appropriate medication depends on the animal and the specific product. Your veterinarian can help determine what’s right for your pet.

How Is Screwworm Treated?

Treatment requires removing the larvae from the affected tissue and thoroughly treating the wound. Your veterinarian may also prescribe medication to kill larvae and antibiotics or other treatment if a secondary infection has developed. Simply killing the existing maggots isn’t necessarily enough. The wound must be properly treated and protected to prevent additional larvae from developing.

Stay Informed, Not Alarmed

New World Screwworm is a serious parasite, but there’s no reason for Queen Creek pet owners to panic. The current U.S. cases are limited to Texas and New Mexico, and federal agencies are actively monitoring and responding to the situation. The most important thing you can do is know the signs, protect your pet’s wounds and seek veterinary care if a wound looks unusual or isn’t healing properly.

If you’re traveling with your pet to or from Mexico, check the latest requirements from USDA APHIS before you leave.

Contact Compassionate Animal Care

At Compassionate Animal Care in Queen Creek, we’re here to help keep your pets healthy and protected. If you have concerns about a wound, parasite prevention, or traveling with your pet, contact our veterinary team for guidance. Contact our clinic today at 480.774.6995. 🐾

Stay informed, check your pets regularly and don’t ignore a wound that doesn’t look right.

Important Resources

For the latest information about New World Screwworm and pet travel requirements, visit USDA APHIS (USDA’s Animal and Plant Health Inspection Service):

USDA APHIS New World Screwworm: https://www.aphis.usda.gov/livestock-poultry-disease/cattle/ticks/screwworm

USDA APHIS Pet Travel: https://www.aphis.usda.gov/pet-travel