Here is a summary of what I found. The screw-worm is the larva of a fly that is twice as big as a house fly. The adult fly lays hundreds of eggs on wounds of warm-blooded animals, particularly livestock and among wildlife frequently deer. In about 12 hours the eggs hatch into the screw-worm maggot which feeds on the injury and grows to maturity in about five days. When fully grown the larva drops to the ground where it pupates into an adult fly, the entire life cycle taking just three weeks.
Infested wounds develop a disgusting smell, drawing other flies.
Animals are literally eaten alive. In areas of high fly densities, infested animals not found are virtually doomed for a slow traumatic death. Clearly the screw-worm is not an attractive insect. Nor has it been an inexpensive pest. Fortunately the screw-worm does not tolerate cold and its population reservoirs remained along the southern United States border.