A parasitic worm eradicated in the United States nearly 60 years ago could be threatening a comeback, Texas wildlife officials warn. The New World Screwworm was recently detected in Mexico, and the Texas Department of Parks and Wildlife is asking people in South Texas to watch out for animals affected by the screwworms.

Just one fly can lay up to 300 eggs at a time and is drawn "to the odor of a wound or natural opening on a live, warm-blooded animal."