Intestinal Parasites in Pets – Holland Street Veterinary Services
Few people are aware that approximately 70 species or groups of species can be found in family pets (dogs and cats) Most parasites are extremely prolific. A single roundworm (toxicara), can lay 200,000 eggs in a single day and to make matters worse, many eggs are resistant to our cold winter climate.

What is a parasite? Parasites make up a large variety of organisms that use the body of an animal to live and reproduce. There are uni-cellular parasite such as Coccidia as well as many different types of intestinal worms. Even though some pets may not show any signs of a parasitic infestation in the early stages, there are symptoms to be aware of including weight loss, diarrhea, loss of appetite, coughing, anemia, and vomiting. A heavy burden of intestinal parasites in young puppies and kittens can on occasion be fatal. In addition,  many intestinal parasites are zoonotic which means transmissible to humans (more on this later).

How do pets become infected with intestinal parasites in the first place?

1.   Ingestion of parasite eggs, or cysts, or ingestion of prey that has parasites (an intermediate host ie. cat eats a mouse that is infected).

2.   A puppy or kitten in utero can be infested by larvae migrating through the body, passing thorough the placenta from the mother to the fetus. Even if the mother had been de-wormed prior to becoming pregnant, she may have parasitic cysts laying dormant in her muscle tissue. Through the process of lactation, these cysts become active and mature, and are passed through the mother’s milk and are ingested by the young. Hence, most puppies and kittens have some degree of roundworm and/or hookworm burden from the time they are born.

3.  Parasites such as hookworm, can also pass through the healthy skin of an animal.

Young pets are more likely to become infected with intestinal parasites because they play and dig and chew on a variety of objects more than their senior counterparts. This puts them at greater risk of ingesting parasite eggs; but adults and seniors are not off the hook (pardon the pun) either. While adults have greater natural resistance due to their developed immune systems, there are several situations that can compromise this defense, and put them at greater risk for parasitic infections. Malnutrition, chronic or major
illnesses, stressful situations (working dogs are a good example), lifestyle change such a move or divorce), allergy drug treatments, major surgeries, cancer and all situations that may weaken the normal  function of the healthy immune system. In addition, there are other groups of animals at greater risk to being infected with intestinal parasites, such as:

  • Adults hunting and ingesting prey
  •  Animals raised in groups (are often stressed due to living conditions), or those that are in poorly kept kennels or catteries. These animals may harbor infections
    for their entire lifetime due to lack of consistent veterinary care.
  • Animals kept in highly contaminated environments, or those that suffer from coprophagia (eating stool).
  • Animals taken to dog parks or that attend shows and trials.
  • Animals that travel to other countries or areas prone to higher risks of infestation.
  • Animals used for breeding.
  • Stray animals.

What is zoonoses? A nifty word for “being transmissible to people”. Parasitic infections and many other infections are said to be zoonotic to people. Dogs and cats infected with worms contaminate the environment by passing eggs or larvae in their feces, and as such may contaminate a large area quickly. Due to the eggs’ resilience to cold, contamination can persist in the environment for years. People contract round and hookworm infections via direct contact with contaminated feces. This usually occurs as a result of accidentally ingesting soil, sand and plant life (ie. not washing produce thoroughly).

What harm can these worms do to humans? Roundworms enter the body when ingested as soon as the eggs hatch into larvae. The larvae then travel through the liver, lungs and other organs causing a condition called “visceral larval migrans”. The larvae can cause damage to tissue and nerves, and may lodge in the eyes causing permanent nerve damage and blindness. A particularly nasty type of roundworm called Baylisascaris procyonis is transmitted by Raccoons and can be fatal to humans. The roundworm larvae cause problems as they travel through the person’s muscles and various organs, including the liver, brain, lungs, and eyes. The severity of the infection depends on how many of the parasite’s eggs were ingested, and where the larvae migrate.

Symptoms in people may include nausea, skin irritations, tiredness, liver enlargement, loss of coordination and muscle control, blindness, inattentiveness, and coma.

Raccoons rarely show symptoms of the disease but the species that don’t usually play host to this worm (such as woodchucks, squirrels, birds) tend to show abnormal behaviors when infested. They’ll tilt their heads and have difficulty walking or climbing. They may lose their fear of people, circle, roll on the ground, fall over, lay on their sides and paddle their feet, or fall into a coma.

If someone has been exposed, or even suspects exposure to raccoon roundworm, seek immediate medical care. If the worms can be killed before they migrate through the body, there’s a very good chance that the disease will beprevented. But if the condition is not treated early, recovery is less assured. Raccoon roundworm infections are very difficult to diagnose in people.

Hookworms penetrate the skin and the larvae move around underneath the skin causing inflammation and irritation. It presents as an angry red, windy itchy trail visible on the surface of human skin. This is called “Cutaneous
larval migrans.” Some hookworms are able to penetrate deeper into human tissue causing more serious damage to the intestines and other organs.

How do I protect my pets and my family?

  • Have puppies, and kittens dewormed at any early age by your  veterinarian  (over the counter dewormers available at pet and grocery stores are ineffective).
  • Start or keep your pets on a preventive deworming program that treats and controls intestinal parasites.

The use of drugs to control parasites is not sufficient alone, so complimentary measures must be implemented to minimize the risk to both our pets and human family members.

  • Have fecal samples analyzed from all pets in the household twice yearly for the first year of life and then annually thereafter.
  • Keep play areas, lawns and gardens around your home free of animal waste on a daily basis. Cover  sandboxes so cats aren’t tempted to use it as a giant litter pan.

Stoop and Scoop! This is one of the best preventive measures anyone can take yet most people are lax about their own backyards.

  • Observe appropriate personal hygiene practices especially before meals and encourage children to do the same.
  • Wear gloves when gardening or working in soil.
  • Discourage wildlife, especially raccoons by not leaving any trash cans outside, and by blocking the underneath of sheds, decks
    etc. so that they aren’t tempted to take refuge there.
  • Have a certain “spot” where you train your dog to do his business. It’s easier to clean one section of the yard thanthe whole thing.
  • Be especially careful about washing after handling pets that are coprophagous.
  • Finally, it is difficult but not impossible to decontaminate soil, but you have to replace the top 15 cm because the eggs stay near the surface.

Sometimes, preventing a parasitic infection can seem impossible, but with a little common sense and preventive measures, you can keep your pets and family free from parasites and the health risks they pose.