If you have ever had a puppy or a kitten or taken in a stray animal, you have likely had a run-in with intestinal worms. Intestinal worms are just one type of parasites that very frequently take up residence in the gastrointestinal tracts of dogs and cats.

While there are lots of internal parasites ‚Äď including multiple varieties of some of those highlighted below ‚Äď for now, we'll be focusing specifically on some of the more common "worms" ‚Äď including one that actually isn't a worm at all!

A few of the more common types of intestinal parasites are:


Slender, whip-shaped, parasitic nematode worms that often infest the intestine of animals, resulting in diarrhea which can be severe and sometimes bloody.


Flat, ribbon-like parasites that live in the intestines of humans and animals. One of the most common indicators of infection are tiny rice-like dried worm segments found on a pet’s bedding.


Among the most common of the intestinal parasites found in dogs and cats. Only roundworms and tapeworms are visible to the naked eye in infected pets’ droppings.


Named for their hooked mouthparts, which fasten to the intestinal walls of the host. They drink the host’s blood, resulting in anemia. Hookworms can also cause gastrointestinal signs like vomiting and diarrhea.


Actually not a worm at all, ringworm is a skin and scalp disease caused by several different kinds of fungi. Ringworm can cause patches of scaly skin in pets and people.

Roundworms and hookworms are most commonly seen in puppies and kittens, who typically acquire these parasites from their mothers in utero, via nursing, or soon after birth from their surrounding environment. Studies have shown that nearly 100% of puppies and kittens have had a parasite exposure at a very young age. Adult dogs are not immune to parasites either and can be exposed to them by coming into contact with a contaminated environment.

Whipworms cannot be transmitted in utero or via nursing ‚Äď instead, infection is caused by the ingestion of eggs from a contaminated environment. Tapeworms, which have a complex lifecycle, are transmitted through the ingestion of an intermediate host, such as a flea.

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Signs your pet may have parasites

Symptoms of intestinal parasites are typically related to gastrointestinal signs, with diarrhea being the most common. Heavily infested pets can also have vomiting and weight loss, and heavy hookworm infections can cause life-threatening anemia in young animals. Infected animals also tend to have dull coats and potbellies.

Testing for intestinal parasites involves looking for parasite eggs in fecal samples, but there can be a high rate of false-negative tests depending on the freshness of the sample, the parasite load and the method used to look for eggs. Because of the risk of a false negative test, routine deworming is the standard of care for all dogs and cats. Puppies should be dewormed every two weeks beginning at two weeks of age through eight weeks of age, and the same goes for kittens beginning at four weeks of age.

Adult pets should have a yearly screening fecal test, as well as a year-round monthly preventative (which can be accomplished by using a heartworm preventative). Unfortunately, there are many ‚Äúhome remedies‚ÄĚ that I frequently hear about, such as garlic and diatomaceous earth, which are not effective against intestinal parasites. The good news is that most dewormers and heartworm preventatives are safe, inexpensive and highly effective.

Another vital way to prevent the spread of parasites is to keep your home and yard clean! Picking up immediately after your dog goes to the bathroom helps to prevent the contamination of your surroundings, and can help keep infections at bay.

Aug 1, 2012
Pet Health

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