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Val Caron Animal Hospital

3055 Highway 69 N
Val Caron, ON P3N 1R8


Internal Parasites of Dogs and Cats:

There are many intestinal parasites that can affect dogs and cats. Roundworms, hookworms, protozoa, heartworm, flukes and tapeworms are just a few examples of what seems an endless list of critters that can affect your pets health. Most of the internal parasites of dogs and cats live in the intestinal tract, but many migrate through the skin or lungs causing problems along the way.

It is just as important to realize that many parasites of our pets can cause illness or disease in humans, so called "zoonotic diseases". In fact the Centers for Disease Control and Prevention ( CDC ) has targeted a number of parasites contracted from domestic animals as  "Neglected Parasitic Infections"

Each pet will have different risks for exposure to parasites based on lifestyle and travel, so parasite prevention is best tailor made between you and your Veterinarian.

Virtually all puppies and kittens get intestinal parasites from their mother. Transplacental, transmammary and direct transmission when a mother vomits for their young, are ways intestinal parasites ensure their life cycle. This is why routine deworming of puppies and kittens, and follow up microscopic anaysis of feces is recommended.

Fortunately, regular deworming and microscopic analysis of your pets feces will keep you and your family safe.

The Campanion Animal Parasite Council has a suggested guidelines for parasite control pet owners should refer to:

Roundworms: Likely the most common intestinal parasite and most common zoonotic parasite in North Amarica. Dogs and cats can aquire a roundworm infestation via ingestion of eggs from the environment, transplacental transmission,transmammary transmission eating raw meat, or eating "intermediate hosts" such as birds and mice.

The clinical signs associated with roundworm infestation can include: ill thrift, pot bellied appearance, vomitting, diarhea, failure to gain weight, coughing and even death in severe cases.

In depth information regarding roundworms:

Hookworms: Hookworms are a serious parasite of dogs and cats, and are the most common cause of "cutaneous larva migrans" in people ( ) . Dogs and cats can become infected with Hookworm via ingestion of larva from the environment, larva penetration through the skin, and ingestion of prey that have infective larvae in their tissues. Transmammary transmission of larva to puppies is an important route of transmission.

Because Hookworms feed off of blood from the digestive tract serious anemia or bloodloss can occur, and can result in death. 

The signs of Hookworm infestation in animals can include: diarrhea, bloodloss, pneumonia, weight loss, iron deficiency, skin disease and weight loss.

For more in depth information regarding hookworms:  

Whipworms: Whipworms are transmitted primarily by ingesting eggs from a contaminated environment. The eggs can persist in the environment for several years. Dogs, foxes and coyotes are the primary host for Whipworms.

Whipworm infection results in bloody diarrhea, wieght loss and dehydration. Whipworm isn't considered a public health risk fortunately.

For more information on Whipworm disease in dogs:

Tapeworms: There actually a large number of species of tapeworms that can infect dogs and cats, and although most don't cause serious disease in our pets they do pose a risk of transmission to people. In fact public health concerns are the most important reason tapeworm control and prevention in pets is important.

Tapeworms can be transmitted to pets by ingesting infected imtermediate hosts such as birds, rabbits, mice,and the viscera of deer and moose. One tapeworm ( Dipylidium caninum ) is transmitted to both pets and people through the ingestion of infected fleas.

Indepth information regarding tapeworms is available at:

Protozoal Parasites: A protozoa is a single celled organism...remember the ameoba from high school biology? There are a suprising number of protozoa that aren't quite as benign as a ameoba unfortunately. Coccidia, giardia, cytauxzoon, erlichia, anaplasma, babesia, hepatozoona and cryptosporidia are all protozoal parasites of North American dogs and cats. Many protozoal parasites of animals can cause infection in people ( zoonotic disease ). In fact Toxoplasmosis is considered one of the most important zoontic diseases and one of the Center for Disease Control's " Neglected Parasitic Infections" ( ).

Many protozoal parasites are actually transmitted by ticks ( tick borne disease ), thus infection is dependent on exposure to ticks for some species. As well potential for exposure to the various protozoa depends on geographic location.

Coccidia: Coccidia infections typically occur in young, stressed or immunosuppressed cats and dogs. Fortunately coccidia doesn't cause disease in people. The clinical signs of a coccidial infection are diarrhea, weight loss, dehydration, and sometimes vomitting. Many adult dogs and cats harbor coccidia, shedding the immature stage ( oocysts ) in their feces, but show no clinical signs. Coccidia can be transmitted by ingesting oocysts from a contaminated environment, and from ingesting prey that have oocysts in their tissues.

Detailed information regarding coccidia can be found here:

Giardia: Also known as "Beaver Fever" giadiasis, causes diarrhea, maldigestion and malabsorption. Giardia is transmitted by fecal-oral contact, contaminated water, and contaminated food. Fortunately transmission of giardia from pets to humans has not been documented.

Detailed information regarding giardia can be found here:


Toxoplasmosis is a protozoal parasitic infection that affects cats and can be transmitted to humans. The most commonly affected organs and tissues include lymph nodes, liver, lung, brain/spinal cord, and the eyes. There may be weight loss, lethargy and fever. Congenital infection with Toxoplasma is associated with neurologic disease, birth defects, stillbirth, and ocular disease. Cats are the primary host for the disease. They can acquire toxoplasmosis by ingesting mammals and birds infected with the parasite, ingesting infective oocysts in the environment (soil, water and vegetation), transmammary and transplacentally.

Toxoplasma infection can cause serious disease in individuals who are pregnant or have a compromised immune system. Humans can obtain the infection by drinking contaminated water, eating undercooked, infected meat, or by accidentally swallowing the parasite through contact with cat feces that contain Toxoplasma. If you are pregnant or immunocompromised, avoid changing cat litter if possible. If this is not possible, wear disposable gloves and wash your hands. It is important to note that unsporulated (not infective) oocysts shed in cat feces require 24 hours to sporulate or become infective. Therefore the litter box should be cleaned every day. In addition, keep your outdoor sandboxes covered and to keep your cat indoors. We highly advise pregnant or immunocompromised to contact their own physician for more details on zoonotic diseases and how to prevent or limit their exposure to them. For more information please visit:


Lungworms: Although lungworms don't seem to be that common in our area, Dr.Hoscheit has confirmed the diagnosis in three dogs in 24 years of practice. The main problem with the diagnosis of lungworm disease is that the lungworm larva don't usually show up in the routine microscopic fecal examination, a special analysis is required.  The clinical signs of lungworm infection in dogs and cats is similar to allergic bronchitis and pneumonia.

Lungworms ( there are seven different recognized species: ) can be transmitted by ingesting slugs, snails, rodents, birds, reptiles, amphibians, or from the saliva or feces of an infected animal. The route of transmission varies from species to species.

Detailed information regarding lungworm can be found here:

Flukes: Flukes are more accurately referred to as trematodes. Our region isn't endemic for flukes, but one fluke on the west coast is the vector of "Salmon Poisoning Disease" and in certain areas of the U.S. (such as Florida) liver and lung flukes can be common.

For more information regarding flukes visit:


Zoonotic Diseases:

For further information regarding parasites and bacteria that can cause illness or disease in people (Zoonotic Disease ) pet owners are referred to:

The Centers for Disease Control and Prevention Medicine

"Who is uniquely susceptable to parasites transmitted by dogs and cats?" 

Complete list of parasitic disease of dogs and cats:

The Companion Animal Parasite Council CAPC has a complete list of all the recognized parasites of dogs and cats, with recommendations for prevention and public health considerations.