Top 5 Most Common Questions about Intestinal Parasites and Deworming

July 7th, 2016 by Daniel Mudrick

Intestinal parasites are one of the most common infections for dogs and cats.


Roundworm larvae pass through the placenta to infect puppies and kittens in the uterus even before they are born, and then still pass through the mother’s milk! Microscopic worm eggs are passed to innocent or unsuspecting pets when they sniff the ground or each other’s fur. Tapeworms pass when pets chew at their fur when it’s itchy from fleas or from hunting.

Clearly, the potential for infection is high.

Here is what you need to know to keep your pets and family safe from intestinal parasites:

1.  How Do I Know If My Pet Has Intestinal Parasites?

When pets are infected with parasites, you may or may not see signs. Hopefully the infection will have been treated or diagnosed (by regular stool checks) before they become ill.

Otherwise, you may see signs of:

  • Enlarged abdomen
  • Dry skin and fur
  • Diarrhea
  • Vomiting (possibly with worms present)
  • Weight loss
  • Loss of energy

Since many parasites are too tiny to be seen, diagnosis is made by microscopic analysis of the stool looking for the eggs, and other microscopic stages produced by intestinal parasites.

2. Why Not Just Test the Stools and Treat when the Test Shows Parasites? 

Testing stool samples for parasite eggs should be done routinely, every couple of months when your pet is young, and at least annually when they are an adult. 

However, on some days the worms produce few eggs, or in many cases the worms are too young to produce eggs. In these situations, we may not find evidence of infection microscopically. Stool samples, therefore, do not demonstrate the presence of parasites 100% of the time.

We do not always depend on a negative stool sample. We include many factors before making a conclusion.

Puppy3. What Is the Safe Plan for Treatment of Worms?

Puppies and kittens are routinely dewormed every 2 weeks until 3 months of age, then again at 4 months. Since the larvae of the worms continue to cycle through pets for several months when they are young, it is important to repeat the treatments. 

If a pet is diagnosed with intestinal parasites, bathing should be done about 1 day after the first treatment. 

These are the guidelines set by the Center for Disease Control (CDC) and by the World Health Organization (WHO), for both the health of pets and people in the household.

4. Can Worms Pass to People? 

Absolutely, yes. Diseases which pass from animals to humans are termed “zoonotic” diseases.  

Several common pet parasites can pass to people in a variety of stages. The symptoms can range from showing no signs, to causing a variety of symptoms including:

  • Skin irritation
  • Diarrhea
  • Development of internal cysts
  • Seizures
  • Blindness

Treating your pets’ intestinal parasites is extremely important for your entire family.

5. How Do I Keep My Family Safe?

We recommend:

  • Cleaning up stools immediately
  • Washing hands after handling puppies and kittens
  • Discouraging face licking, especially for children and people with compromised immune systems
  • Ensure you have a fresh stool sample checked microscopically at least annually
  • Provide a sample for the follow-up test if worms were found on a previous sample
  • Make sure to follow all deworming protocols according to directions
  • Cover sandboxes, which cats may use as a toilet
  • Be very careful, if raccoons are around, to wear gloves and wash hands well when working in the garden
  • Have children wash before eating and when coming indoors

Pregnant (or possibly pregnant) women should not clean or change the cat litter, should wash hands well after gardening, and only eat well-cooked meat or fish.   

Click here to read more about intestinal parasites and deworming!

If you have any more questions about this important topic, please don’t hesitate to ask us. For a great resource, visit

We have a variety of vaccinations, topical treatments, and pills which will help prevent your pets from getting parasites throughout the warm seasons. Book your appointment today to safeguard your pet’s health.

We are a 24/7 emergency veterinary hospital in Mississauga – call us at 905-855-2100 right away if your pet needs immediate care! A veterinarian is always present, never just “on call”!

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About Daniel Mudrick

I'm the owner and founder of Clarkson Village Animal Hospital, a state-of-the-art veterinary hospital that's open 24 hours a day, 7 days a week, 365 days a year. Clarkson Village Animal Hospital has always been a dream of mine, and by caring for one patient at a time, the hospital has continued to grow. During those rare times when I'm not at the hospital, I'm at yoga, hiking, gardening, and spending time with my family. I also enjoy reading to stay current on the most recent advances in veterinary medicine.

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