HEALTH CAMELID
Description of M-Worm
verses Gut Worm

By Dr. Steve Hull, First Published on Alpacasite chat list 6/09
Reprinted From SELR newsletter Volume 3, Issue 3 September
1, 2009

There remains a LOT of misunderstandings on parasite control.
First, we MUST know what we are talking about. There
are two general types of internal worms that camelid owners
worry about and must manage.

The first, and easiest is the M worm, brain worm, meningial
worm or the worm that goes up the spinal cord, eats nerve/
brain tissues and causes paralysis, blindness and then death.
Then there are gut parasites.

M worm first (I prefer to call it BRAIN worm as this conceptually
separates it from gut worms). For those of you east of
the Mississippi (and a few sections just west of that - eastern
Texas, SE Oklahoma, parts of AK, etc) your parasite control
must be the following: Ivermectin injected EVERY month, all
year long, at a dose of 1 ml/100 lbs (source -Dr. Steve Purdy,
Director U-Mass Camelid Program). For brain worm, there
is no blood test, fecal test, or other test that can test for “eggs”.
You must do prevention. (ed note: some research indicates a 1 ml/70
lbs. or less - check with YOUR vet!)

Now let’s consider gut worms. In the USA, ivermectin was a
tremendous parasite killer - from the late 60’s up to about 1012
years ago. Since then virtually all gut parasites have become
resistant to it (but NOT M worm). Thus, using ivermectin
against gut worms is just worthless - and it gives you a dangerous
false sense of security. Ivermectin simply got over used and
in situations where it was not needed (like taking antibiotics
for a viral cold).

The key to a proper gut worming strategy is to give up on the
“spring and fall” or just fall, or once every other month worming.
Rather use fecal exams to find out if you have gut worms.
Then ONLY worm if you have a problem! Otherwise you are
just worming “blind” not knowing what you are doing. Th e
use of blind worming has resulted in the massive gut ivermectin

resistant parasite problem. Let’s not repeat that with the
drugs that currently do work on gut worms.

Further adding to the confusion is that the brain worm larvae
are ingested by mouth and start off in the gut. So these must
also be gut worms - right? Then there are well meaning vets
that also get confused, don’t keep up or whatever.

Wrong. The problem is that alpacas and a few other animals
are aberrant hosts and the M worm does NOT stay in the gut.
Rather, it invades the spinal cord and as it travels to the brain,
it eats nerves.

The treatment for M worm is very expensive, not a 100%
cure and meanwhile the disease is terribly painful to the animals
and they suffer. If you understand the use of monthly
heartworm for your dog, then the EXACT same logic applies
to your alpacas and the use of monthly injected ivermectin.
Yes, the use of monthly ivermectin for M worm will cause gut
parasite resistance - but they are resistant already. So that bull
is out of the gate, out of the pasture long gone - and it doesn’t
matter that the gate is still open!

We are now seeing another gut parasite that is deadly - Haemonchus
contortus (aka, barberpole worm, goat worm, H.
contortus). This is one that drinks blood and lives in the true
stomach (not rumen). It literally bleeds the animal dry internally
and can reproduce at a very fast rate (just s couple of
weeks). And no, it is NOT just in the south (Texas) it is now
all over the USA.

Bottom lines. If you are east of the Mississippi (and a few other
areas), you need to do the monthly ivermectin shots all year
long (good news - this is inexpensive) . Others need to check
for fecal parasites (with a vet that knows how to do it with a
centrifuge or 24 hour float) and then ONLY worm if you have
a problem. And after you worm, you must check two weeks
later to make sure the parasites you treated for are dead. Th e
amount of times you need to check for fecal worms depends
on where you live. Dry lot may only need a once per year if
you have a closed herd. But if you send a lot of animals in/out
or are in wet and warm areas, then more frequent is necessary.
You need to manage that.

Yes, I know that you are on dry lot and that you “never have
worms”. Do you have females in for breeding to your males?
Do you send animals out for breeding? Do you ever visit other
farms and then bring home poop on your shoes? Yes, yes, yes, I
do all these things and that is why I must check for gut worms
and THEN use the appropriate wormer.

Dr. Hull can be contacted by e-mail at steve@timberlakefarms
and is available for consults.

LAMAS News November 2009 
 

Kansas State University Issues Benefit-Cost Analysis of the National Animal Identification System – Camelids Given Lowest Priority