Intestinal Parasites in Your Dog


Statistics show that one in three dogs at some time can be infected with intestinal parasites such as roundworms, hookworms, whipworms, and tapeworms.

The following is a list of the common intestinal parasites that infect your dog, what they are, how your dog can possibly acquire them, its harmful effects to your dog and to you,


(Toxocara canis, Toxascaris leonine)


Most common to infect the animal kingdom, roundworms grow 2 – 4 inches long, tan or white creatures with tapered ends that look like spaghetti.

How they are acquired Puppies are usually born with them. Those infected with roundworms have a potbelly or a bloated look and dry, scaly coat. When your pets are in unsanitary conditions, don’t be surprised if your dog becomes infested. Unlike hookworm eggs, roundworm eggs are very resistant to drying, sunlight or antiseptics. They can last for years in soil and still be infectious.

Harmful Effects to your Dog If in huge numbers, a dog may vomit these worms or discharge them all as a whole in the fecal matter. Roundworms can cause diarrhea – the infestation’s effect is evident on your pet’s general appearance. They can also cause intestinal blockage and stool cannot pass if they become too many.

Harmful Effects to Man Since roundworms are zoonotic, they can be transferred to humans. They cause an infection known as “Visceral Larva Migrans”, which result in inflammation of muscle tissue. Young children are susceptible to transfer and can experience eye inflammations leading to blindness.


Usually used to treat roundworms are pyrantel pamoate, fenbendazole and piperazine, both classified as Anthelmintics or dewormers.


(Dipylidium caninum)


Tapeworms can be seen unlike other parasites. Tapeworm segments, usually white in color, can be seen after in the dog’s feces or rectum after elimination that broke off from the adult. How they are acquired Fleas can carry tapeworm eggs, so the ingestion of parasite eggs is the only way to infection.

Harmful Effects to your Dog Although they don’t cause much harm to our canine friends, tapeworms cause pet owners to squirm at their ghastly sight. Dogs experience cramping and sometimes gas.

Harmful Effects to Man Children can accidentally swallow fleas that have eggs, causing intense discomfort. Fish can also be an intermediate host – so be careful in eating raw fish.


Antiparasitic agents, praziquantel and epsiprantel are both used both by oral medication or injection.


(Ancylostoma caninium)


Hookworms are blood-sucking intestinal parasites and are invisible to the naked eye. How they are acquired Puppies can acquire hookworm eggs from their mother and unhygienic surroundings or soil. Heat and dryness kills hookworm eggs quickly.

Harmful Effects to your Dog

If your dog is infected, their feces look abnormally blackish and loose. In the first week of infection, they may look healthy, but extreme infections in injured or young dogs can be lethal. They can cause intestinal bleeding leading to anemia and bloody diarrhea.

Harmful Effects to Man

In humans, hookworms can also cause intestinal bleeding especially to children. In adults, they can cause an infection known as “Cutaneous Larva Migrans” or “creeping eruption”. Lesions that can be really itchy are caused by hookworm larvae nestling into the skin usually in the feet. More so, when severe, they can cause abdominal pains and eye problems.


Hookworms can be diagnosed by the examination of the pet’s fecal matter. Dewormers include pyrantel pamoate and fenbendazole. An example of a product is Heartgard.


(Trichuris vulpis)


Another unseen freeloader is the whipworm, which is the most difficult to exterminate. They do not need to leave the intestines to complete a life cycle. Eggs are passed in the dog’s stool and after 2-4 weeks in a warm, moist environment, they become infective to another dog. The eggs hatch and the worms mature in the cecal area of the intestine where they can cause chronic bowel inflammation.

How they are acquired

Most common in adult animals especially those housed in groups or kennels because they can become infectious to other dogs after a few weeks in a warm environment.

Harmful Effects to your Dog

The symptoms may include severe diarrhea, flatulence, loss of weight and general overall condition. Whipworms can cause chronic bowel inflammation.

Harmful Effects to Man

Luckily, these parasites only adhere to our canine friends.


Fenbendazole (Panacur) is usually prescribed after diagnosis. To regulate these parasites, give doses of milbemycin oxime every month, a heartworm preventive medication. 

Please note: This article is part of a collection of dog-related content that we purchased the rights to. Opinions expressed may or may not agree with those espoused by Master Dog Trainer Adam G. Katz. When in doubt, please refer to the advice given in Adam’s dog training book.  This article is provided for your enjoyment, only. It’s relevance to real world working dog training may be limited.