Roundworms in Dogs

Roundworms in dogs are caused by the Toxocara canis and the Toxocara leonis parasites which are located in the intestinal tract of the dog. The dog will have a pot bellied appearance and poor skin and hair condition; the symptoms of the parasite will be more severe in puppies. The parasite can be treated once it is detected. The roundworm may affect humans also, by the ingestion of the Toxocara canis eggs that may be present in the soil or sand. The parasite may cause vision problems in humans.

Transmission of Roundworms

The roundworm may be transmitted though direct contact with an infected dog, through the ingestion of parasite eggs or from mother to puppy through birth and lactation.

The parasite is a long, tubular and white colored worm that can get to the size of up to 5 inches and can be vomited or eliminated through feces.

Symptoms of Roundwork Infection in Dogs

A dog with roundworm infection will present the following symptoms:

  • Poor skin and hair condition, hair loss
  • Lack of appetite
  • Dehydration
  • Diarrhea
  • Liver disease
  • Pneumonia
  • Vomiting
  • Pot bellied appearance
  • Colic

The symptoms are more severe in puppies.

Diagnosing Roundworms

Roundworms can be diagnosed judging by the above mentioned symptoms and through a fecal flotation examination. The feces typically contain eggs of the parasite that can be identified through the microscope.

Treating a Canine Roundworm Infection

The roundworms may be eliminated though a cure of dewormers. A lot of puppies are born with the roundworms, so the pregnant mother can receive dewormers starting from the third trimester of the pregnancy (day 40 to 44 of pregnancy). The puppy should also receive safe dewormers until the age of 12 weeks.

The most common dewormers for roundworms include fenbendazole or pyrantel pamoate. The eggs must be also eliminated, to make sure the dog is worm free.

The vet will prescribe the right dosage suitable for your dog.

Over the counter dewormers are not recommended, as they may not eliminate all the worms.

How to Prevent Roundworms

A pregnant dog should undergo a deworming procedure to prevent the transmission to the puppies. After the puppy is born, dewormers should also be administered.

As roundworms can e transmitted through the ingestion of the infected soil, you should keep your dog away from eating sand and soil.

After a deworming treatment, the dog’s environment should be properly cleaned and any traces of feces should be removed to prevent the re-infection with the worms.

As the feces can contain eggs and the parasite can be transmitted to humans also, you need to wear surgical gloves every time you handle the feces. Wash your hands and maintain a proper hygiene to prevent infection.


If the dewormers are properly administered, the dog will be healthy.

In rare cases, the worms can be fatal in puppies, causing intestinal obstruction and being able to migrate to vital organs such as lungs or liver.

In puppies, undetected roundworms can lead to stunted growth, in case the worms are transmitted from the mother.