Human infections caused by the New World screwworm fly, Cochliomyia hominivorax , have reemerged in Mexico after the country was declared free of the parasite in 2003. A study published in the CDC’s Emerging Infectious Diseases examined cases reported between April 2025 and March 2026 and identified 204 confirmed human cases, highlighting the need for greater clinical awareness as the infestation continues to spread northward. New World screwworm is an obligate parasite during its larval stage. Female flies are attracted to wounds, inflamed tissue, mucous membranes, and natural body openings, where they deposit eggs.

The eggs can hatch within 12 to 24 hours, and the larvae subsequently invade and feed on living tissue for approximately 5 to 7 days. Unlike some forms of myiasis that primarily involve necrotic tissue, C. hominivorax can cause rapidly progressive tissue destruction. The…