Cochliomyia

Cochliomyia is a genus in the family Calliphoridae, known as blowflies, in the order Diptera. Cochliomyia is commonly referred to as the New World screwworm flies, as distinct from Old World screwworm flies. Four species are in this genus: C. macellaria, C. hominivorax, C. aldrichi, and C. minima. C. hominivorax is known as the primary screwworm because its larvae produce myiasis and feed on living tissue. This feeding causes deep, pocket-like lesions in the skin, which can be very damaging to the animal host. C. macellaria is known as the secondary screwworm because its larvae produce myiasis, but feed only on necrotic tissue. Both C. hominivorax and C. macellaria thrive in warm, tropical areas.

Both species thrive in tropical areas which are warm and humid. C. macellaria is the most common species of the two in North America, distributed throughout northern South America, Central America, Caribbean Islands, the United States, and southern Canada.

C. hominivorax was distributed throughout the northern South America, Central America, Caribbean Islands, and the United States prior to the use of the sterile insect technique, after which it was eliminated from the U.S. and Mexico. However, the bordering Central American countries serve a challenge to keep the species eliminated since these countries still have populations of this fly. Many of these countries continue to implement elimination programs.