Learn from a veterinarian near you about the common internal dog parasites and how they affect your pet

A parasite is defined as an organism that inhabits a host, feeds on him, and harms it in one way or the other. Parasitic infestations are quite common in dogs. Some parasites live on the outside, while others feed on the internal organs of the dogs. In this article, we will discuss the 3 most common internal parasites that infest domestic dogs and pose a threat to their health and wellbeing.


The following two types of roundworms are commonly found in dogs:

  • Toxocara canis (T. canis) – this strain can be transmitted to humans as well
  • Toxascaris leonina.

Roundworms live in the intestine of dogs. Female dogs pass on this parasite to their pups, hence many puppies are born with these parasites. To protect the health of your puppy, it is important to detect the presence of roundworms early on and provide proper medical care to the puppy. Untreated roundworms multiply in number rapidly and cause several health issues which can even lead to death.

  • Baylisascaris procyonis (B. procyonis) is a rare strain of roundworm that is found in some parts of North America. Dogs acquire this strain by ingesting the eggs of infected hosts such as rodents, birds, and rabbits. B. procyonis is especially dangerous because humans can contract this strain from infected dogs as well.


  • Tapeworms infest the intestines of dogs as well. These parasites are acquired through the ingestion of infected fleas or by eating such animals that are already plagued with tapeworms. Once the tapeworm gets inside the dog, the eggs hatch and attaches themselves to the intestinal lining of the dog.

In the USA, the most common type of tapeworm that affects dogs is Dipylidium caninum. This parasite is passed from fleas whether they infest the outer body of the dog or are ingested mistakenly.

  • A common way to detect tapeworm infestation is by analyzing the dog’s stool. Tapeworms exhibit as little pieces of rice in the dog’s stool. Another sign is that infected dogs scoot their bottoms along the ground to get rid of the irritation caused by tapeworms. If you detect any of the above signs, take your dog to the vet and get him the recommended treatment.


  • internal dog parasitesHeartworms are the most dangerous types of worms that infect domestic dogs. These worms are transmitted through mosquito bites. The worms enter the bloodstream of the dog and reach their hearts where they develop in size. Heartworms can reach up to a foot in length. Mature heartworms clog the dog’s heart and cause inflammation in the arteries. This disruption in blood supply causes the heart to work harder. As a result, it deteriorates rapidly.

Over time, the flow of blood decreases in the infected dog. Some common signs of heartworm infestation are:

  • Mild and continuous cough
  • Fatigue
  • Reduction in appetite.

If left untreated, heartworm infestation will cause cardiac arrest in dogs. Treating a full-blown heartworm infestation is both expensive and draining for the dog. In some cases, surgery is required to remove the parasites. All vets emphasize the prevention of heartworm infestation through the use of regular medicines and the application of topical lotions.

Common Symptoms of Parasitic Infestations in Dogs

Following are the most common signs of parasitic infestations:

  • Diarrhea
  • Dehydration
  • The appearance of blood in stool
  • Anemia
  • Loss of appetite
  • Rapid weight loss
  • Pneumonia
  • Blocked intestines

To ensure the wellbeing of your dog, consult our team of expert vets at Autumn Trails and Veterinary Center. We are located in Charlottesville, VA. to book your appointment, call us at 434-971-9800.