How do screwworms affect animals?

Written and fact-checked by

The Editors of Encyclopaedia Britannica

Screwworm maggots develop in surface wounds or mucous membranes of animals after a female fly deposits 200–400 eggs near these sites. The larvae burrow into the tissue and, when mature, drop to the ground to pupate. Severe infestations, known as myiasis, may kill the affected animal, sometimes in as little as one or two weeks.