Starr County, TX (KRGV) — The U.S. Department of Agriculture confirmed two New World screwworm cases in Starr County, including an active case in a dog.

The agency said it also found another screwworm case in cattle in Starr County. As of Thursday, the USDA website listed 56 active screwworm cases.

screwworms are flesh-eating parasites whose larvae infest open wounds. Cases have also been found in Arizona and New Mexico.