Myiasis

Myiasis is the infestation of vertebrates by the larvae, or maggots, of numerous species of flies. These larvae may invade different parts of an animal's body or may appear externally. Some invertebrates, such as spiders, may be also attacked by species of Sarcophagidae, the flesh flies. Myiasis of such domestic animals as horses, sheep or cattle, is of considerable economic importance. Cattle afflicted with cutaneous myiasis produce poor-grade hides full of small perforations; while infestation by screw worms, if untreated, results in death. Horses afflicted with the stomach bot become emaciated and may die.

In cutaneous myiasis, the larvae are found in or under the skin. There may be a migration of some species of these larvae through host tissues, resulting in swelling and intense itching. Intestinal myiasis in man is usually the result of accidentally swallowing the eggs or larvae of these flies. It commonly occurs in many herbivores who ingest the eggs while feeding on contaminated herbage. The larvae settle in the stomach or intestinal tract of the animal host.