Summer Sores (Habronematidosis)
Treatment of summer sores is time consuming and the sores themselves don’t heal quickly. The sores are ugly, annoying, and nasty-looking, but they do eventually go away. So, in addition to all of the other things, you also need a good dose of patience - David Ramey DVM
HWN Suggests
Summer Sores
In my experience, and also as written in the veterinary literature, worrying too much about killing the parasite may be mostly a waste of time. That’s because the inflammatory reaction set off the by the tissue is not only hard on the tissue (and ugly), it’s also hard on the parasites. In fact, the inflammatory reaction itself kills the little buggers. So, at least according to the literature – and this is supported by my own experience – spending a lot of time deworming affected horses, or applying deworming pastes, or products that contain deworming pastes, directly to the summer sores may not add that much to the treatment protocol. It certainly won’t hurt the horses – it’s just that it…
Articles of Interest
Summer Sores "bug" Horses
So what are summer sores exactly? Well- it’s fascinating and disturbing all at the same time. Summer sores are officially known as habronemiasis or granular dermatitis. They are caused by the larvae of Habronema spp worms that cause parasitic infections in horses' stomachs. Normally, stable flies buzzing around manure will pick up larvae that hatched in manure and deposit them in moist areas (typically near the mouths) of horses, which then swallow them and continue the lifecycle in the stomach. These internal infections are usually controlled with the deworming medication Ivermectin/ Moxidectin. The trouble arises when these Habronema larvae are deposited in other moist areas like the penis sheath, the corner of the eyes, wounds, or any moist skin of the horse.
What You Need to Know About Summer Sores in Horses
Strategies involve killing the parasite plus calming down the inflammation so the lesions can heal. Ivermectin and moxidectin (see box) are effective against most stomach worms. For the inflammation, your veterinarian may prescribe topical or systemic glucocorticoids, or a topical mixture of steroids and DMSO. Excess granulated tissue may also need to be surgically removed or frozen off with liquid nitrogen. Antibiotics may be necessary if a secondary infection has set in.
