Screwworms can be dangerous to humans, particularly in areas experiencing an outbreak. The larvae of the New World screwworm (Cochliomyia hominivorax) infest open wounds and other body openings, where they burrow into and feed on living tissue. This can cause severe tissue damage, intense pain, secondary bacterial infections, and, in rare cases, death if left untreated. People at greatest risk include older adults, individuals with untreated wounds, agricultural workers, and residents of rural areas where screwworm flies are circulating.
As of June 2026, health authorities have reported more than 2,100 human cases across Mexico and Central America during the ongoing outbreak. No locally acquired human cases have been reported in the United States.