In the U.S., New World Screwworm only has been found in Texas and New Mexico. New World Screwworm larvae infest living tissue of warm-blooded animals, causing infection, which can cause potentially deadly damage to the animal. The U.S. first suspended imports of cattle from Mexico in November 2024 after New World Screwworm was found there. ADVERTISEMENTHorn flies, stable flies and face fliesWhile New World Screwworm has garnered headlines, other flies and pests remain larger economic concerns for northern livestock producers. If New World Screwworm does infect an animal, he stresses that there are treatments.