Deworming Adult Dogs

Most veterinarians recommend that adult dogs be dewormed only when there is specific reason to do so, such as when eggs or parasites are found during a fecal examination. Dogs can also be kept on a yearlong heartworm preventive that also protects against many of the intestinal parasites. All dogs should have a fecal examination done at least once a year.

Most dogs carry ascarids as encysted larvae, but intestinal infestation by the adult worm is rare in the healthy dog. Hookworms are likely to be a problem in adults only during periods of stress. Only milbemycin (Interceptor) is effective against encysted hookworm larvae.

Whipworms are a frequent cause of acute and chronic diarrhea in adult dogs. They are difficult to diagnose on routine fecal examination. Eradication requires the use of specific agents not commonly used for other worms.

Tapeworms are common in dogs but, fortunately, cause few symptoms. The worm segments are easy to detect in the stool. Threadworms are not common. Very few agents are effective against this parasite.

A brood bitch should have her stool checked before breeding. If parasites are found, she should be dewormed. Deworming during pregnancy should be done only as determined by your veterinarian. Note that some dewormers are contraindicated during pregnancy.