New Delhi, June 4 -- The New World screwworm fly has reached south Texas, the U.S. Department of Agriculture confirmed Wednesday, the first time in decades that the parasite with flesh-eating larvae has threatened the nation's cattle industry and only the third time it's appeared in the U.S. in that time.

Agriculture Secretary Brooke Rollins said the case was in a 3-week-old calf in LaPryor, Texas, about 50 miles (80 kilometers) from the Mexico border. Texas State Veterinarian Bud Dinges said he has established a 12-mile (20-kilometer) quarantine zone, prohibiting the movement of any warm-blooded animal - including pets - outside that zone without an inspection.

Rollins said there have been no other detections of the fly in the U.S., an...