What Are the Symptoms of Roundworm Infections? How You Might Know if Your Pet Has Roundworm

What Are the Symptoms of Roundworm Infections?
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Roundworm infections in pets can result in vomiting, diarrhea, and other symptoms, though sometimes there will be no signs of the infection. Learn about the symptoms of roundworm infections.

Roundworms are parasites that can infect a dog or cat’s intestinal tract or other bodily tissues, ultimately causing malnourishment, as the parasites consume the pet’s food and block the intestines.

Some pets with roundworm will not exhibit any symptoms for several months. This can be because the worms are dormant within the body, or are still in their egg life stage, or that there aren’t enough worms to cause a notable change in your pet’s behavior or nourishment.


The most common symptom of a roundworm infection is diarrhea, sometimes with the worms, which can grow to several inches long, visible in the stool. This can be shocking and scary to see, and while your pet will need to see a veterinarian and get started on deworming medication immediately, the worms themselves will die once they are outside your pet’s body. The stool will also contain roundworm eggs, which will be ready to re-infect the same or another host in one to a few weeks. For these reasons, keep your pet’s litter box or your yard clean on a regular basis.

The eggs in the stool will be microscopic, but a veterinary test will be able to identify them. 

Other Common Symptoms of Roundworm

Pets with roundworms will sometimes:

  • have a pot-bellied appearance
  • vomit
  • cough
  • lose weight
  • and lose the healthy shine to their coats.

Blockage and Intussusception

If left untreated, a severe roundworm infestation can block the pet’s intestines and lead to death. An intussusception may occur, which means part of the intestine has telescoped within another part, causing blockage.

Aberrant larval migrans

In some cases an aberrant larval migrans can occur, which means the larval stage of the roundworm failed to migrate to the lungs or intestine, and can instead cause damage to another organ, like the eyes.

If your dog or cat has roundworms, treatments like deworming medications are very effective.

More on Parasites in Pets

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Symptoms of Hookworms in Pets

This information is for informational purposes only and is not meant as a substitute for the professional advice of, or diagnosis or treatment by, your veterinarian with respect to your pet. It has, however, been verified by a licensed veterinarian for accuracy.

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