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Roundworms in Dogs & Puppies

By Colleen Williams and medically reviewed by Brittany Kleszynski, DVM
September 19, 2018 • 2 min. read
sick dog

Roundworms, also known as ascarids, are a type of parasite that inhabit and feed off your dog’s intestines. They are usually white to tan in color, measure a few inches long, and resemble small noodles.

Roundworms are incredibly common in puppies since they can be transmitted from mother to offspring. They can lead to malnourishment since the roundworms feed off the nutrients within the intestines. Young dogs are more vulnerable to the parasite because their immune systems have not yet fully matured.

Two main species of roundworms include Toxocara canis and Toxascaris leonina. Toxocara canis is much more prevalent in the dog population and can lead to serious illness.

Dogs can become infected by ingesting contaminated feces or other animals harboring roundworm larvae, such as rodents or birds. As mentioned above, roundworms may also be spread from mother to puppy. The life cycle of a roundworm is complicated. There are several stages they must go through as they make their way through the dog’s body before settling in the intestines where they can feed indefinitely.


When infected with roundworms, some dogs might not show any symptoms until the worm burden gets very high. In some cases, you may see worms in your dog’s feces which can prompt a veterinary visit.  In other cases, the following symptoms may be present:

  • Malnourishment
  • Weight loss
  • Abdominal enlargement (potbelly appearance)
  • Coughing
  • Vomiting
  • Diarrhea
  • Belly pain
  • Dull coat
  • Worms in vomit or feces

To confirm a diagnosis of roundworms, your dog’s veterinarian will conduct a fecal test by analyzing a small sample of stool under a microscope. If roundworms are present, the veterinarian will begin treatment.


There are several safe and effective deworming treatments available for roundworms. The treatments are administered orally in a liquid or tablet form. It’s important that you administer the medications as prescribed by your veterinarian and follow-up for a repeat fecal test to ensure the parasites have been eliminated.


Though roundworms are very common, you can prevent high worm burdens by starting a deworming regimen early in your puppy’s life. Puppies should be dewormed every 3 weeks until they are at least 16 weeks of age. Your veterinarian may recommend annual deworming treatments for adult dogs as a preventative measure. Medications that prevent heartworms can also prevent and treat roundworms.

Keep your home clean and your dog’s area sanitized. Regularly remove any feces from your yard and clean up after your dog every time they defecate in a public place. If you can, keep your dog away from dead animals that might carry roundworms.

Can I get roundworms from my dog?

Yes. It is rare, but if you come into contact with feces or dirt that’s contaminated with roundworms, you could become infected. Roundworm infections in humans could lead to eye, lung, heart, or brain problems in a process called visceral larval migrans.

Children are at higher risk because they tend to touch their mouths with their hands more often. Keep kids away from areas where dogs defecate. Make sure kids in your home wash their hands regularly and keep their areas sanitized.

By enrolling your dog early, conditions and illnesses like parasite infection treatments will be covered up to 90% by your Healthy Paws dog insurance. Find out more by getting a free quote.

The content is not intended to be a substitute for professional veterinarian advice, diagnosis, or treatment. Always seek the advice of your veterinarian or other qualified health providers with any questions you may have regarding a medical diagnosis, condition, or treatment options.

colleen williams
By Colleen Williams

Over the past decade, Colleen has written about health, wellness, beauty, and even pets for The New York Times, The Cut, Refinery29, xoVain, Healthy Paws Pet Insurance, and Seattle Met Magazine, as well as many beauty brands. She has a BFA in Art History from the University of New Mexico and an AAS in Fashion Design from Parsons School of Design in New York.

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About DVM contributor, Brittany Kleszynski
By Brittany Kleszynski, DVM

Dr. Brittany Kleszynski is a freelance veterinary and medical writer for Healthy Paws who specializes in creating meaningful content that engages readers and speaks directly to the intended audiences. She writes and edits educational articles for pet parents and creates continuing education and online learning modules for healthcare professionals. She has worked in research and small animal practice since graduating veterinary school and is a member of the American Veterinary Medical Association.

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