Myiases

Myiases are infestations of live animals or humans by fly larvae (maggots). The condition is caused by dipteran species whose larvae feed on living tissue (obligate or primary myiasis) or on necrotic tissue and debris (facultative myiasis). Obligate myiasis-causing species, such as certain Cochliomyia or Chrysomya species, require living tissue to develop, whereas facultative species, including some Lucilia and Phormia species, typically exploit wounds, ulcers, or necrotic tissue. Dermatobia hominis is a well-known human agent in some regions.

Life cycle and transmission typically involve a female fly laying eggs or larvae near or on a suitable host. Eggs hatch into larvae that invade wounds, or penetrate intact skin in the case of obligate myiasis. The larvae feed on tissue over a variable period before dropping to the ground to pupate. Transmission is often associated with poor wound care, open wounds, or exposure to flies in warm, humid environments.

Clinical features vary by species and site but commonly include painful, enlarging wounds with tissue destruction, foul odor, swelling, and secondary bacterial infection. In animals, myiases can cause reduced weight gain, tissue damage, and secondary complications.

Diagnosis is usually based on clinical examination and presence of larvae in wounds, with species identification by larval morphology or molecular methods. Treatment involves prompt mechanical removal of all larvae, wound debridement, antisepsis, and management of secondary infection. Systemic antiparasitics such as ivermectin may be used in extensive infestations. Prevention focuses on wound protection, good hygiene, fly control, and protective measures in areas where myiasis is prevalent. Prognosis depends on the extent of tissue involvement and timeliness of treatment.