Intestinal Parasites and Deworming

Intestinal parasites are one of the most common infections for dogs and cats. Our pets have a high potential for infection due to the many varied ways they can contract intestinal parasites.

For example, roundworm larvae can pass through the placenta to infect puppies and kittens in the uterus even before they are born; microscopic worm eggs can pass to unsuspecting pets when they sniff the ground or each other’s fur; tapeworms can pass when pets chew at their fur when it’s itchy.

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.

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.

Why Treat for Worms when the Stool Test Was Negative? 

Routine treatments are required because the incidence of parasites is so high, and it poses a health risk both to pets and people.

It is actually good news when the stool sample is negative, because the worms present are young, who are not yet producing eggs. This means less risk for re-infection of your pet, less risk for your family, and less contamination of the environment. 

Why Bother Checking Stool Samples at All?

Firstly, stool samples are performed to help assess the success of deworming treatments of confirmed cases.

Stool checks are also required routinely to check for the other parasites that are not treated by the standard deworming treatment (Giardia, Coccidia, Tapeworms, etc.), and to check for more unusual parasites (Physaloptera, Paragonimus, Alaria).

Skin parasites (Sarcoptes, Demodex mites) may show on stool samples, after pets chew their itchy skin and swallow the microscopic mites. This is an unexpected but effective means of diagnosing skin mites.

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.

What If My Pet Was Dewormed at the Breeder before I Got Them? 

Any deworming treatments done before you got your pet were just the beginning of the deworming program. There is a huge difference between receiving deworm treatment(s) and being free of worms. 

Furthermore, medications used by breeders or humane societies are not as effective as the medications we use in the veterinary hospital. Products available over the counter at pet stores are not effective, have very limited treatment ranges, are often outdated, and often have significant toxicity concerns.

There is no room for error when dealing with the health of people and our pets.

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.

How Do I Keep My Family Safe?

We recommend cleaning up stools immediately, washing hands after handling puppies and kittens, and discouraging face licking, especially for children and people with compromised immune systems. 

Ensure that 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, and make sure to follow all deworming protocols according to directions.

Make sure to 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, and for children to 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. 

If you think your pet may have a parasite, or you would like to schedule a check‐up, just click here to book your next appointment.

Sign Up for Our Monthly Pet Newsletter Mississauga Veterinary Hospital

Get Pet Health Tips and Clinic News

  • This field is for validation purposes and should be left unchanged.

Request Your Vet Appointment

The basic exam fee is $88.10 + HST. We look forward to seeing you and your pet soon!
  • This field is for validation purposes and should be left unchanged.