- Cochliomyia hominivorax, commonly known as the New World screwworm, is a highly destructive parasitic fly that poses serious risks to both animals and humans.
- Belonging to the family Calliphoridae, this species is infamous for causing obligatory myiasis, a condition where its larvae infest and feed on the living tissue of warm-blooded hosts.
- Unlike other blowflies that primarily consume decaying matter, C. hominivorax targets open wounds, mucous membranes, and even natural body openings, leading to severe tissue damage, secondary infections, and, in untreated cases, death.
- The adult screwworm fly is metallic blue-green with distinctive orange eyes and three dark stripes on its thorax.
- Female flies lay batches of eggs near wounds or moist body openings of livestock, pets, and occasionally humans. Within 24 hours, the eggs hatch into larvae, which immediately burrow into the host’s flesh, feeding for 5–7 days. These maggots have a characteristic screw-like appearance due to rows of spines along their bodies. Once mature, they drop to the ground to pupate in the soil, emerging as adult flies after about a week.
- This parasite has had a devastating economic impact on livestock industries, particularly in the Americas. Before eradication efforts, it caused massive losses in cattle, sheep, and other livestock due to fatal infestations.
- The Sterile Insect Technique (SIT), developed in the mid-20th century, successfully eliminated screwworms from the United States, Mexico, and Central America by releasing radiation-sterilized male flies to disrupt reproduction. However, the species remains endemic in parts of South America and the Caribbean, requiring ongoing vigilance to prevent reintroduction.
- Human infestations, though rare, can occur when flies lay eggs in open wounds, nasal passages, or ears. Symptoms include intense pain, swelling, and foul-smelling discharge. Treatment involves surgical removal of larvae, wound cleaning, and antibiotics to prevent infection. Preventive measures for livestock include regular wound inspections, insecticidal treatments, and quarantine protocols for infected animals.
- The New World screwworm remains a critical example of both the dangers of parasitic flies and the success of scientific pest control. Continued monitoring and sterile insect programs are essential to protect agriculture and public health from this relentless parasite.
