TEXAS — The Animal and Plant Health Inspection Service (APHIS) confirmed a second New World screwworm case in Texas on Friday evening.

APHIS, which falls under the purview of the U.S. Department of Agriculture (USDA), said in a release that officials detected this second case “after testing a number of suspect cases” in Zavala County, which sits roughly 30 miles south of Uvalde. The screwworm infected a one-month-old calf about 5.6 miles from the first case site, which involved a three-month-old calf.

New World screwworms are parasites that produce flesh-eating larvae in warm-blooded animals, from livestock to wildlife to even, sometimes, humans. The USDA announced the original case on Wednesday after sending the pest to Iowa for testing.

That screwworm became the first in Texas since 1966, according to the Associated Press. Until then, they were considered eradicated in North America thanks to a program that released sterile male screwworms into the population.

In 2024, the New World screwworm reached Mexico after migrating from South America. Then, in January, Gov. Greg Abbott made a disaster order in response to the parasite’s migration north.

USDA has confirmed a second detection of New World Screwworm in a one-month-old calf in Zavala County, Texas — approximately 5.6 miles from the first case.

With our partners in Texas, we are responding with speed and strength.

— New World Screwworm Rapid Response (@Screwworm_RR) June 5, 2026

With a second confirmed case, APHIS said in a release that it has an on-site strike team in Texas that “includes veterinary medical officers and animal health technicians.” An entomologist is assisting with expedited case confirmations in Kerville, thanks to the National Veterinary Services Laboratories.

Since Thursday, the USDA has been releasing sterile flies in the impacted Zavala County area, and a 20-kilometer infestation zone with quarantines is in place. Along the border, the USDA is carrying out increased screwworm trapping.

“We have defeated this pest before, and we will do it again,” a post from New World Screwworm Rapid Response, an official USDA account, said on X. “America’s livestock producers have USDA’s FULL support.”