Large Mouthed Stomach Worm

Latin Name: Habronema muscae

The adults live in the stomach. Eggs are passed out in the droppings, hatch and are picked up by fly maggots feeding in the dung. The worm larvae develop within the maggot and are then found in the mouth-parts of the fly.

Horses become infected when they swallow the larvae that are released from the flies as they feed around the lips, nostrils and wounds of horses.

Larvae deposited on sores and wounds do not complete their life cycle but cause intense irritation. Wounds fail to heal (persistent 'summer sores').

The Merck Veterinary Manual - picture of habronema

Worming Programme    Drugs to use to combat worms    Worming Information    Worms that affect horses