[Myiasis: a practical approach]

Myiasis refers to the infestation of humans or other vertebrates by dipteran larvae that feed on living or necrotic tissue. It occurs worldwide, particularly in tropical and subtropical regions. Furuncular myiasis presents as a painful, erythematous, furuncle-like nodule with a central breathing pore, often accompanied by serous discharge and a sensation of movement. In Central and South America, it is caused by Dermatobia hominis, whereas in sub-Saharan Africa, Cordylobia anthropophaga is the predominant causative species. While D. hominis transfers its eggs to humans via blood-feeding arthropods, C. anthropophaga is commonly transmitted through contaminated clothing dried outdoors. The larvae develop obligatorily in the subcutaneous tissue; development takes several weeks for Dermatobia and typically 1-2 weeks for Cordylobia. The disease follows a progressive course and does not respond to antibiotic therapy. Treatment consists of mechanical removal of the larva followed by local wound care. Tetanus vaccination status should be assessed and updated if necessary. Antibiotics are indicated only in cases of bacterial superinfection. Migratory myiasis results from the migration of dipteran larvae within the skin and presents with intensely pruritic, serpiginous or linear skin lesions. Important causative agents include Gasterophilus and Hypoderma spp. Treatment consists of complete removal of the larva. Aggressive wound myiasis results from the infestation of open or necrotic wounds as well as skin neoplasms by dipteran larvae. In facultative myiasis, larvae of the family Calliphoridae feed on devitalized and necrotic tissue. This characteristic forms the basis for the therapeutic use of larvae of the species Lucilia in maggot therapy, which is employed for wound debridement in necrotic or fibrin-covered ulcers. In contrast, obligate myiasis can cause tissue destruction, pain, and secondary bacterial infections through damage of viable tissue. Treatment involves complete removal of the larvae, thorough wound cleansing, and debridement. Where clinically indicated, antibiotic therapy may also be required.