The following resources are for informational purposes
only. Please consult your vet. to determine the best
program for you & your horse in your geographical
location.
Summer Sores
Summer sores are caused by the infected
larvae of stomach worms, which are deposited into skin abrasions
on horses. Learn how to control and prevent these unsightly skin
lesions.
By Jayne Pedigo
All horse owners have to deal with the nuisance
of summer insect pests. It seems to simply be part of life
around horses. However, some of these pests aren't just a
nuisance, they can actually cause a health hazard to your
horses.
Case in point is the common fly. Among other
things, flies can carry the larvae of two different types of
stomach worm, Habronema muscae and Draschia megastoma,
known as Spurids. When these larvae are deposited on skin
abrasions, they can cause skin lesions known as summer sores.
These sores can heal up quickly in winter, but
often recur in the warmer months of summer, hence the name. The
lesions seem to cause intense itching and horses will chew and
bite at them, delaying the healing process and in many cases
allowing secondary infections to occur.
If you've had to deal with summer sores, you
will know that topical applications of antibiotics and salves
aren't fully effective. They seem to start responding and then
come back again. When the horse bites and chews at them they can
quickly take on a bloody and unsightly appearance. In order to
control the larvae that cause the infection, it's necessary to
apply an anthelmintic directly to the site. Dichlorvos and
Trichlorfon have been shown to be effective in treating summer
sores.
Prevention is better than cure and the
prevention of choice is a strict deworming program. Ivermectin
is effective against the Spurid larvae which cause summer sores,
so a deworming program which includes at least two treatments of
Ivermectin each year will control both summer sores and stomach
worms.
