Roundworm in Dogs

Roundworm is also called “raccoon disease” since it is usually picked up from eating raccoon feces or the dirt where they have been.  Roundworm is the parasite Baylisascaris procyonis.  It does not seem to hurt raccoons but can be fatal to puppies and seriously injure adult dogs.  Roundworm can also be caught by ingesting an animal infected with it. Dogs that catch wild animals and consume them are at greater risk of getting this disease than dogs that do not do this.

Roundworm is found throughout the United States.  Because roundworm can attack the brain and nervous system, it may mimic the symptoms of rabies.  If rabies is suspected, the dog should be tested for B. procyonis.

There are two types of roundworm infestations in dogs:  intestinal infection and visceral disease.  When roundworm eggs are ingested, they then hatch and migrate to the intestines.  There they grow some more before they begin their final migration into the viscera (the organs in the abdominal cavity), the nervous system, or the eye.  Infection in the abdominal cavity is called visceral larval migrans (VLM), infection of the nervous system is called neural larval migrans (NLM) and infection of the eye is called ocular larval migrans (OLM).

Adult dogs most often get the intestinal form of the infection.  Puppies, however, most often get the NLM type of the disease.  Usually, there is no outward signs of an infection until the worms start attacking the nervous system.  Signs of this include:  unsteady walking and loss of coordination or muscle control, difficulty eating or swallowing, lethargy, lying down excessively, circling, seizure, confusion or lack of attention.

If the dog has an infection of viscera, it may present with symptoms of liver and/or lung disease, while infection of the eye may not be obvious until the dog has gone blind.

The cause of all this is the ingestion of round worm eggs.  This usually occurs from eating raccoon feces, or the dirt where they have been, or eating a small animal such as a rabbit that has been infected.

The intestinal form of the disease may be found by doing a fecal smear.  The other forms of the disease are usually found when investigating another disease, such as rabies, vision problems, or distemper.

If your dog has the intestinal form of the disease, he will be given one of these drugs:  pyrantel pamoate, febantel, praziquantel, ivermectin, mibemycin oxime.  For the larval form, the dog is given corticosteroids and long-term albendazole.

Your dog will be checked two weeks after treatment and probably given another dose of the medicine to eliminate any intestinal larvae.  The dog should be checked again in a month to make sure the disease is gone.

This parasite is zoonotic, and can cause serious illness in humans, especially children.  Raccoon feces should be removed from the property, especially sand boxes.  An infected dog’s waste should also be removed promptly.  Use gloves when doing this to prevent you from contracting this debilitating parasite.