ridecamp@endurance.net: belly sores due to worm

belly sores due to worm

Glenda R. Snodgrass (grs@consider.theneteffect.com)
Tue, 22 Jul 1997 19:36:15 -0500 (CDT)

Some of you may remember that I posted a question about a month ago about
topical ointments, mentioning a line of sores down Lakota's belly that I
thought was due to fly/gnat bites being infected and infested. One
Ridecamper mentioned a parasite that could cause these sores (thanks,
Alice!). I decided to try the topical ointments first, and religiously
applied Swat, Furazone, Corona and Ichthammol in succession, about a week
each. The sores would get a little better, then get worse again.

Finally, I had the vet look at him today, and behold! he's got a worm.
Whaddya know. I got all the details from the vet, so read on if you want
to know more (I took notes, so hopefully I got this all straight).

There are three related worms: Onchocerca reticulata, Onchocerca linea
and Onchocerca cervicalis. These are filial threadworms like heartworms.
These worms take literally years to develop into adult worms that cause
skin eruptions. Cervicalis migrates to ligaments in the neck and causes
sores on the shoulder or withers area, while reticulata and linea reside
in the ligaments/tendons of the abdomen (spleen, liver, stomach) and erupt
in sores either in a line straight down the belly or a patch near the
girth. As the worms die in the open sores, it can itch pretty badly, so
horses with cervicalis (shoulder sores) will often be seen scratching
themselves on any available service. Belly sores can't hardly be
scratched, so it's less obvious with the other two types.

Lakota had a series of oblong-shaped sores in a straight line under his
belly from just behind the girth to just in front of the sheath. The
sores lost all hair, and would periodically swell into a knot and open up
into raw/bloody sores, where small flies and gnats would feast -- which is
why I thought this was a really bad case of fly/gnat bites getting
re-infected. Rigorous application of thick, smelly antiobiotic ointments
(Corona and Ichthammol) would clear up the raw spots and swelling for a
couple of days, then it would come back (while I was still continuing
treatment).

Thanks to Alice, I decided to call in the vet to ask about worms, and hit
paydirt. <g>

In the Gulf Coast area, standard treatment for this parasite is two
massive doses, about three weeks apart, of Ivermectin, given
intravenously. The vet said he was giving about 10 times the amount you
would get from a single tube of paste. He said this is usually a
permanent solution. Regular Ivermectin paste will keep the young worms
under control, but is not strong enough to kill adult worms. Since the
worms take years to develop, older horses like Lakota (10yo) who didn't
get Ivermectin years ago could easily have picked up the worms and
quietly nurtured them. The worms are transmitted through flies, and may
passed to all the horses in the surrounding area. However, any
nearby horses being wormed every 8 weeks with Ivermectin paste should not
be affected, as the paste controls young worms. He recommended that I
continue the topical ointments until the sores are gone, to minimize
bacterial infection.

The vet said that these sores are often mistaken for dermatological
problems, fungus, bacterial infection, etc. Only the specific location of
the sores is unique. So if you have sores like these in these locations,
which don't get better after a couple weeks of standard treatment, I
suggest you call the vet to talk worms.

The End of Snodgrass' Vet Course, Part I <g> Any vets on this list, feel
free to correct anything you think I got wrong. I am repeating
(correctly, I hope) what I was told by Dr. Dukes of Mobile, Alabama.

Glenda & Lakota (worms? I'm not wormy! Am I?)

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