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MENINGEAL WORM INFECTION IN GOATS

If  you raise goats  in areas of high rainfall where the land holds water and  whitetail deer are abundant , you should be concerned about Meningeal Worm infection  in your  goats.

Sometimes called deerworm  or   brainworm, the parasite Parelaphostrongulus tenuis  uses the whitetail deer as its host and passes through the deer's body without harming it.    In  goats, the deerworm seems to "get lost" and winds up in the spinal canal,  causing hind leg weakness and unsteadiness that  progresses  to hind leg dragging,  inability to walk in a straight line,  head wobbling from side to side, tremors, and finally inability to stand.    Once the larvae migrate over the body,  the goat oftentimes (but not always) experiences intense itching and may begin chewing holes in its hide.    Shaving the hair off  the sites where itching and chewing are occurring will usually reveal a straight line of  hard nodules  over which the skin has thickened  leading from the spine.   These are the subcutaneous larvae migrating throughout the goat's body.    Pregnant does may abort from either the stress of the disease or the treatment given.

Goats who develop  Meningeal Worm infection get it by ingesting the intermediate host, a slug or snail, while browsing in wet areas such as ponds or swamps  or under dead leaves, branches, and trees.  Warm weather in early winter and subsequent  lack of snow cover  has made this disease  common in the eastern part of the United States.  If you also raise alpacas, llamas, or related ruminants, you  will find that these camelids are even more susceptible to Meningeal Worm infection  than goats or sheep.

You  should suspect Meningeal Worm disease  if the goat displays bare patches of hide from quarter to palm size (generally on the flank or near the front leg), a bloody hole chewed in the hide, neurologic signs or  problems  involving the spinal cord, from hind  leg dragging to inability to get up.  The disease can be a slow progression of symptoms or can strike suddenly.  Neurological damage expresses itself with a wobbly hind end  while the head is fine and the goat has a good appetite.    Pneumonia is a common secondary proble because the goat is down and inactive.   Most animals do not seem to be in pain (other than the itching), and  most eat and drink well  until they die.

The curative treatment (treatment for infected goats displaying symptoms)  has been updated.   Very high dosages of  fenbenzadole (Safeguard/Panacur)   at a dosing rate of ten (10)  times the label dosage.   Liquid Safeguard's label dose is 2.3 cc (ml) per 100 pounds bodyweight, which means that you must multiply this by 10 and dose at 23 cc (ml) per 100 pounds bodyweight.   You can use Safeguard paste, also dosing at ten times the label's dosage rate based upon the goat's body weight.  Treatment is given once a day for five consecutive days.  Ivermectin was eliminated from the preventative treatment because researchers at Ohio State University found that it didn't penetrate the spinal column to kill the worms, so once neurological symptoms appeared,  using Ivermectin was ineffective.   If the goat is down and can't get up on its own, the chance for recovery  is  not good.  An anti-inflammatory drug like Banamine can be useful in alleviating the inflammation of nerve tissue.    Dexamethasone may also be used, but it will  cause abortions in pregnant  does.

This treatment, if  utilized early in the disease, can stop its progression but cannot undo any nerve damage.  Permanent spinal damage (including curvature), hindquarter weakness,  and/or inability to deliver kids  may be the residual effect of Meningeal Worm infection.   Once the spinal cord is damaged,  treatment can only do so much and the goat will never be back  to full health.    You should let   one month pass after treatment is completed before deciding that the treatment worked or that the goat needs to be euthanized.

The preventative treatment  for goats showing no symptoms whatsoever involves   high dosages of  1%injectable ivermectin given orally followed by  oral dosing of   Safeguard/Panacur.    Ivermectin paste or pour-on are not effective in preventing meningeal deerworm infection.  One-percent (1%  injectable Ivermectin  should be given at a rate of 1 cc per 55 pounds bodyweight for at least three days,  followed by a double-the-cattle dosage (4.6 cc per 100 pounds bodyweight) of  fenbendazole (Safeguard or Panacur) for five days.   Using  1% Ivermectin preventatively (prophylactically) or to treat pre-neurological symptoms is effective.

In the northern and eastern parts of the United States, most infections occur in late summer/early fall or early winter, following a wet summer and mild fall.  The larval migration of P. tenuis can take from ten days to over three months, so some goat raisers  are using 1%  injectable Invermectin  preventatively on a monthly basis  for up to four months during the at-risk seasons.   If the expense of this preventative treatment is too high, then you should treat your goats preventatively at least one time during Meningeal Deerworm season and again if any symptoms occur in any goat.   Remember that frequent use of dewormers can result in the barberpole stomach worm  developing resistance to the dewormer's ability to control  Haemonchus Contortus, so you must constantly do FAMACHA field checks and fecal counts to keep this worm  under control.

Although laboratory testing of the cerebrospinal fluid  produces an accurate diagnosis, the key to treatment of Meningeal Worm infection is early aggressive treatment.     If all indications are  that the goat is infected with P. tenuis,  forget  testing and  immediately start  treatment.

Prevention is difficult.  The only proven preventative medication is  oral dosing of  1%  injectable Ivomec in combination with Safeguard/Panacur given orally once a month  during slug and snail season.   Fence off ponds and swamps so goats cannot become exposed to slugs and snails.   Treatment can be unsuccessful, even when the disease is caught in its early stages.  Prevention is the key to avoiding this devastating disease.    Remember that goats are a dry-land species, and other than needing to drink clean uncontaminated water,  moisture is the goat's enemy.

Suzanne W. Gasparotto, Onion Creek Ranch, Texas   1.1.21