03/06/2026
Cutaneous Habronemiasis aka Summer Sores. These sores typically occur in more tropical climates, but are becoming more common in the UK. They are caused by a type of (harmless) stomach worm, Habronema, that has part of its life cycle in flies.
If horses get small abrasions on their lips, flies can deposit the larval stage of the worm into the abrasion that then develops into larger, non-healing sores.
These sores don’t tend to heal on their own, and should resolve after a one off dose of wormer. If they don’t then heal, further investigation is required as other causes of non-healing wounds can be a foreign body (e.g a thorn) or a sarcoid.