Texas reinforced the alert for the New World screwworm, a pest that can cause serious injuries to livestock, pets and wild animals, and which sparked the response of state and federal authorities after confirming cases in animals.

The issue is of particular concern to the livestock sector, but it also raises an inevitable question for the population: can it affect humans? The response from health authorities is clear: yes it can occur, but it is rare, and so far no locally acquired human infestations have been reported in the United States.

The United States Department of Agriculture confirmed on June 3, 2026 the presence of the New World screwworm in a calf from Zavala County, Texas. Since then, the state expanded emergency and surveillance measures to prevent the plague from establishing itself in the country again.

What is the New World screwworm?

The New World screwworm is not a common worm, but the larva of a parasitic fly known scientifically as Cochliomyia hominivorax.

Unlike other larvae that feed on dead tissue, these larvae can penetrate open wounds and feed on living tissue. This can cause serious injuries, secondary infections, loss of animals and heavy economic damage for livestock producers.

The Animal and Plant Health Inspection Service of the US Department of Agriculture (USDA) considers it a serious pest because it can affect livestock, pets, wildlife and, less frequently, people and birds.

What cases were confirmed in Texas

The first USDA-confirmed detection in this current outbreak occurred in a three-week-old calf in Zavala County, South Texas.

Can screwworm affect humans?

Yes, it can affect humans, but cases are rare and the current risk in the United States remains low, according to the CDC.

The parasite can infest open wounds or mucous membranes of warm-blooded animals. That includes livestock, pets, wildlife and, to a lesser extent, people. CDC reported that no locally acquired human infestations have been reported in the United States during the current outbreak.

Even so, authorities recommend not ignoring suspicious injuries. A wound with maggots, increasing pain, bad odor, discharge or damaged tissue should be evaluated by a doctor. In animals, any suspicion should be reported immediately to a veterinarian or animal health authorities.

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Why it worries farmers and pet owners

The main threat is in animals. Flies can lay eggs in small wounds, cuts, navels of newborn animals, or skin lesions. When the larvae hatch, they begin to feed on living tissue. If not detected and treated in time, the infestation can progress rapidly and cause severe damage.

For ranchers, the risk is not only health. An advance of the screwworm can cause movement restrictions, quarantines, increased veterinary costs, productive losses and economic damage in rural areas.

For pet owners, the recommendation is to check wounds, keep them clean and consult the veterinarian if unusual signs appear.

What is Texas doing?

Governor Greg Abbott issued a New World screwworm disaster proclamation on June 5, 2026. The measure seeks to accelerate state coordination, strengthen emergency response and support surveillance, detection and control actions.

According to authorities, the pest poses a risk to livestock, agriculture, wildlife and the Texas economy. That's why they recommend frequently checking farm animals, pets, and wildlife in care, especially if they have open wounds.

Warning signs may include visible larvae, bad odor, inflammation, bleeding, discharge, irritation, pain, or unusual behavior of the animal.

In case of suspicion, it is not recommended to try to solve the problem without reporting it. Producers should contact a veterinarian, the Texas Animal Health Commission, or USDA APHIS to activate appropriate protocols.

In humans, the recommendation is to seek medical attention if a wound worsens, has larvae, or shows signs of infection. Although the current risk to Americans is low, early detection is key.