Megan Van Emon, Extension Beef Cattle Specialist, Montana State University
New World Screwworm (NWS) is a species of fly (Cochliomyia hominivorax) that lays eggs in the wounds of living warm-blooded animals. Eggs hatch within 12-24 hours into larvae that burrow into the wound to feed. Burrowing creates a larger wound that can lead to illness and death if not treated.
The fly was once native to the Southern United States and was eradicated in 1966 with the targeted release of sterilized male flies. Since females only mate once in their lifetime, mating with a sterilized male fly resulted in unf...