Texas discovery of ‘devastating’ flesh-eating fly that lays eggs in animal eyes prompts new regulations in Tennessee

NASHVILLE, Tenn. (WSMV) – The New World Screwworm, a flesh-eating fly that lays eggs in animal orifices, has been detected in Texas, prompting new temporary regulations in Tennessee.

The Tennessee Department of Agriculture said Friday that it has issued new temporary animal import requirements after the screwworm was found in Texas.

The USDA announced the first U.S. case of the New World Screwworm on Wednesday, saying it was confirmed in a 3-week-old calf in Zavala County, Texas. The larvae was found in the bovine’s umbilical area, the USDA said, calling it “a devastating pest.”

“It can cause serious, often deadly damage to animals and people in areas where the pest spreads,” the USDA says. “While NWS is present in parts of South America — where infections in animals and people continue to occur — it was eradicated from the United States decades ago. In recent years, NWS has moved northward through Central America and Mexico and was confirmed in Texas on June 3, 2026.”

There have not been any other cases of the New World Screwworm in the U.S.

The Tennessee Department of Agriculture said there is no indication of an outbreak in the state, but that officials wanted to issue temporary animal import requirements to help educate and prevent one from occurring.

As part of the order, the interstate movement of certain animals coming into Tennessee has been restricted. The order applies to animals imported from “infested zones, infested states, and high-risk counties.”

Animals imported from outside an infested zone, but within an infested state or high-risk county, will be required to obtain a Certificate of Veterinary Inspection declaring they do not have signs of the flesh-eating fly.

“The CVI must include the statement, ‘All animals listed on the CVI have been inspected and are free from screwworm larvae infestation,’” the state said. “The CVI shall be valid for no more than 7 days from the date of inspection.”

Animals imported from an infested zone will need a CVI saying they were given effective treatment for the screwworm. Documents must also provide information about the treatment that was given, entry permit numbers, signatures from authorized representatives, and more.

The full list of requirements and exemptions can be found HERE.

What is the New World Screwworm?

The Centers for Disease Control and Prevention (CDC) says that the New World Scerwworm is a parasitic fly that eats “the tissue or flesh of warm-blooded animals and people.”

“NWS flies are attracted to wounds and body openings like the nose, eyes, ears, and mouth, where they lay eggs,” the CDC says. “The eggs hatch into maggots (larvae) that eat live tissue, causing a worsening, often painful and foul-smelling wound.”

They eat that tissue, the CDC says, by using “sharp mouth hooks,” adding that the wound will become “larger and deeper as more larvae hatch and feed on living tissue.”

While the fly has typically been found in South America and the Caribbean, the CDC says it has been steadily moving more north since 2023.

“NWS infestations (presence of maggots on or in the body) do not regularly occur in the United States, but cases have occurred in travelers returning from areas where flies are present,” the CDC says. “If you travel to these areas, have an open wound and spend a lot of time outdoors, you may be at greater risk of becoming infested with NWS.”