Myiasis is the infestation of live human and other vertebrate animals with dipterous larvae, which, at least for a certain period, feed on the host's dead or living tissue, liquid body substances or ingested food (Zumpt, 1965). The animal importance of myiasis is well known and well described in the veterinary literature; the frequency of human myiasis is greater than generally realized in Europe or North America. Inasmuch as infestations are self-limited, the presence of larvae may go unnoticed and unreported unless there is a secondary bacterial infection. The diagnosis of myiasis is easily overlooked in Europe because of its relative rarity.

Most myiasis-causing flies belong to one of three major families: Oestridae, Sarcophagidae or Calliphoridae, although representatives of other families, such as Muscidae and Phoridae, also are known to cause myiasis.

An aetiological classification of myiasis-causing flies separates them into three forms of myiasis: obligate, in which it is necessary for the maggots to feed on living tissues; facultative, where flies opportunistically take advantage of wounds or degenerative necrotic conditions as a site in which to incubate their larvae; and accidental, which occurs when egg-stage flies are ingested on contaminated food or come in contact with the genitourinary tract. In general obligate myiasis of humans is tropical in origin, whereas facultative and accidental myiasis can occur anywhere in the world. In the furuncular form, boil-like lesions develop gradually over a few days. Each lesion has a central punctum, which discharges serosanguinous fluid.