Invisible Pest, Massive Stakes for Ranchers

New World screwworm is back in Texas, and federal officials are moving fast to keep it from turning into a larger livestock disaster.

Quick Take

USDA confirmed the first U.S. animal case in the current outbreak on June 3, 2026, in a calf in Texas ^[1]^[3]
Officials say the current risk to people in the United States is very low ^[3]^[7]
The response includes surveillance, movement controls, and sterile fly releases ^[2]^[3]
Ranchers are being told to watch wounds, navels, and other body openings closely ^[1]^[4]

What Was Confirmed in Texas

The United States Department of Agriculture confirmed New World screwworm in a bovine in Zavala County, Texas, after larvae were found in the calf’s umbilical area. The agency calls the pest serious because the larvae burrow into living tissue and can cause major damage to livestock. Officials also said there were no further detections at the time of the announcement ^[1].

The case matters because screwworm is not a normal fly problem. It is a parasite that lays eggs in wounds and openings on warm-blooded animals, then the larvae feed on living flesh. Texas animal health officials say early detection is critical, and they urge producers to report suspected cases quickly and avoid moving animals until they get guidance ^[4]^[8].

Why Federal Officials Are Treating This as a Livestock Threat

Federal and state agencies are treating this as an agricultural emergency, not a food safety scare. The USDA says the U.S. food supply remains safe, and the Centers for Disease Control and Prevention says no locally acquired human infestations have been reported in the United States. At the same time, the disease can cause painful wounds, tissue loss, and death if it is not treated early ^[3]^[7].

The real danger is to cattle, wildlife, and pets, especially in warm border states where the fly could spread fast. Texas A and M AgriLife says the pest can infect livestock, wildlife, pets, and, in rare cases, people. Its researchers also warn that if the fly reestablishes itself, the losses could be severe for cattle and hunting interests in Texas ^[8]^[12].

How the Response Is Supposed to Work

USDA says the response includes active surveillance, animal movement controls, outreach, and sterile fly releases. In public remarks, Agriculture Secretary Brooke Rollins said the department has already started releasing sterile flies in South Texas and is working with Texas officials on checkpoints, landowner coordination, and fly-release sites. The plan is meant to break the breeding cycle before the pest spreads farther ^[2]^[3].

🚨New World Screwworm Update🚨
15 cases have been confirmed in total across the U.S, with 12 cases active in Texas. We have been preparing for this, and I am working with USDA @SecRollins to combat this pest, protect our livestock industry, and mitigate economic impacts. Read the…

— Rep. Monica De La Cruz (@RepMonicaDLC) June 22, 2026

That response also shows why this issue hits a nerve with rural America. Screwworm was once driven out of the United States through a long eradication campaign, and USDA materials describe that effort as one of agriculture’s biggest success stories. Its return is a reminder that border control, animal health, and food security all connect, even when the human health risk stays low ^[6]^[7]^[21].

What Ranchers and Pet Owners Should Watch For

Officials want owners to look for draining or enlarging wounds, visible maggots, and signs of discomfort. They also say to check the nose, ears, genitals, and the navel of newborn animals, since those are common entry points. If a case is suspected, Texas officials and USDA ask people to contact animal health authorities right away and keep the animal isolated ^[1]^[4]^[8].

For now, the story is one of containment, not collapse. The confirmed U.S. case is serious, but federal health guidance still says the human risk remains very low, and that no local human spread has been found. The bigger test is whether the government can stay ahead of the fly with steady surveillance, fast reporting, and disciplined livestock controls before the pest gets a foothold again ^[3]^[7]^[14].