warble fly

Large, brownish, hairy flies, with mouthparts that are reduced or vestigial. The larva is a large maggot covered with spines. They cause myiasis (invasion of the tissues by fly larvae) in animals.

In agriculture, warble flies are pests, causing damage to livestock, where their presence can retard growth, reduce milk and meat yield, and render hides worthless.

The larvae of Oestrus ovis normally invade the nasal cavities of sheep and goats, and those of Hypoderma are skin parasites of cattle and other animals, causing ‘ulcers’ in the skin, a condition called warbles. In humans Oestrus invasion is rare, except for shepherds and goatherds, and the larva is more often noticed attempting to penetrate the eye than the nasal cavities. Hypoderma attempts to follow its normal pattern, migrating from the site of the bite to the shoulders or neck.

Classification