Common canine intestinal parasitic diseases

Roundworm is the most common canine intestinal parasitic disease. Photo: Dominik QN/Unsplash

Dogs at any age are susceptible to these common canine intestinal parasitic diseases – Roundworm, Hookworm, Whipworm and Flea Tapeworm. However, puppies are at a greater risk!

Some of these parasites in dogs pose a significant risk to humans, particularly children. So, it’s important that your puppy or adult dog is protected against these nasty canine intestinal parasitic diseases.

Roundworm (Toxocara canis and felis)

Roundworms are the most common of the canine intestinal parasitic diseases. Most dogs become infected with them at some time in their lives, usually as puppies. Younger dogs are especially vulnerable to roundworms because their immune systems are not fully mature yet and they aren’t able to fight off the adult worms as effectively as an adult dog can.

How is it transmitted?

Dogs are often infected with Roundworms prenatally. The eggs have been picked up by the mother but fail to complete their life cycle and form cysts in her tissues. The hormonal changes of pregnancy causes them to migrate into her puppies. Roundworms can also develop in a puppy after it is born when the puppy ingests eggs from the environment or suckles worm larvae (young Roundworms) in the bitch’s milk.

A less common way of infestation is when Roundworm lavae are present in the tissues of a mouse or another small mammal and the puppy eats the animal.

What are the signs of Roundworms?

Major Roundworm infections can cause the following signs in puppies:

  • Diarrhoea
  • Vomiting
  • Weight loss
  • Dull coat
  • A potbellied appearance

A heavy burden of Roundworms may cause intestinal obstruction.  Adult Roundworms may be vomited or appear in your dog’s faeces – they are several centimetres long and look like strips of elastic or pasta.


Your vet can provide a quality de-wormer that will safely and effectively get rid of the worms.

Roundworm risk to humans

Roundworms do pose a significant risk to humans, usually children who can ingest them in soil contaminated with dog faeces. The parasite can travel to the eye, lung, heart and cause neurological signs.

Children should not be allowed to play in areas where there could be dog faeces. Practice good hygiene after playing and definitely before eating.

Hookworm (Ancylostoma canninum)

The Hookworm is a tiny parasite that attaches to the lining of the intestinal wall and feeds on the dog’s blood. It’s eggs are shed into the digestive tract and pass into the environment through the dog’s faeces.

How is it transmitted?

Larvae (young Hookworms) that hatch from hookworm eggs live in the soil. These larvae can infect dogs by ingestion or through contact and penetration of the skin.

What are the signs of Hookworm?

Hookworms suck blood and therefore cause internal blood loss. They are a serious threat to dogs, especially young puppies that may not survive the blood loss without transfusions.

The signs in a dog:

  • Looks unhealthy and the linings of its nostrils, lips, and ears will be pale
  • Poor appetite
  • If hookworm larvae get into the lungs, the dog will cough
  • Dark and tarry stool, diarrhea, and constipation
  • Weight loss


Hookworms cannot be seen with the naked eye and must be therefore be microscopically examined by your veterinarian through a stool specimen. The treatment is as for Roundworms.

Hookworm risk to humans

Hookworm larvae can penetrate the skin as well as be swallowed. The signs of Hookworm depend on the route of entry but can include skin irritation, diarrhea, intestinal bleeding and moderate to severe abdominal pain.

Whipworm (Trichuris vulpris)

Whipworms attach to the wall of the cecum, which is where the small intestine and large intestine meet (in your dog). The worms are shaped like a whip.

How is it transmitted?

Dogs become infected with Whipworms by swallowing infective whipworm eggs from ingesting contaminated soil, food or faeces in the ground.

What are the signs of Whipworm?

Dogs that are infected with a few whipworms may not have any signs of infection but more severe infections can cause:

  • Bloody diarrhea
  • Abdominal pain
  • Dehydration
  • Anemia
  • Weight loss

If an infected dog is not treated, then severe whipworm infection can cause serious disease and even death.

Treatment for Whipworm

The veterinarian will confirm the diagnosis by conducting the faecal flotation procedure on a stool sample.

Your veterinarian can prescribe safe and effective products that will treat and control both the worms and larvae living within the dog’s body.

Whipworm Risk to humans

Whipworm is not transmissible to humans.

Flea Tapeworm (Diplidium caninum)

The flea Tapeworm is a long, flat worm that attaches to the dog’s small intestine. It consists of a ‘head’ or scolex and a number of segments each with its own reproductive organs.

How is it transmitted?

All Tapeworms have an immediate host (necessary for the completion of the life cycle), which the dog eats to become infected. For the flea Tapeworm it is the flea.

What are the signs of Flea Tapeworm?

As the flea tapeworm attaches loosely to the dog’s intestine and feeds on digested food, dogs usually are not sick, so not cause pain and do not lose weight from the worms.

They are generally only diagnosed by the presence of segments in the dog’s faeces, which look like grains of rice or seeds and often wriggle. Tapeworm segments are visible with the naked eye. They are generally seen around the dog’s anus or on the faeces.

Your dog may ‘scoot’ on their rear end on the ground but this is often due to infected anal glands.

Treatment for FleaTapeworm

If you think your dog is infected with tapeworms, call your veterinarian for an appointment to get an accurate diagnosis and safe, effective de-wormer treatment.

Tapeworm risk to humans

People may pick up Tapeworm segments from the ground and develop an asymptomatic infestation.

3 steps to protect your dog and family against canine intestinal parasitic diseases 

  1. Pick up your dog poo! Internal parasitic diseases control should focus on daily removal of faeces in your yard and prevention of dogs having contact with faeces in public places like the dog park.
  2. Because fleas are an immediate host for the most common type of tapeworm, you’ll need consistent, effective flea control.
  3. Talk to your veterinarian about the appropriate worming protocol for your dog. Puppies should be treated at 2, 4, 6 and 8 weeks of age and then receive a monthly treatment until 6 months. Nursing mothers should be wormed with their puppies to decrease the risk of transmission.  A 3 monthly worming with a broad spectrum anthelmintic for adult dogs is recommended or the use of heartworm control which also controls intestinal worms.