Toxocara Canis in Dogs

Mature roundworms feed on the partially digested food located in a dog’s intestines.  The parasite takes nutrients and nourishment away from the dog. Puppies are more susceptible to roundworms because their immune systems are not fully developed. Toxocara canis is more common in warm, wet and tropical areas.

If your dog is showing symptoms of having roundworms or if you visually see “spaghetti type” worms in his vomit or stool, he should be seen by a veterinarian as soon as possible. Untreated roundworms can cause malnutrition and may be lead to intestinal obstruction or rupture.

Toxocara canis is a species of roundworm. Toxocara canis is the most common parasitic worm found in dogs.  This species of roundworm can be transmitted to people by contact with contaminated feces or soil.

Symptoms may include:

• Mild to severe diarrhea
• Vomiting
• Gagging
• Weight loss
• Weakness
• Dull hair coat
• Poor skin condition
• Loss of appetite
• Abdominal pain - Whimpers or cries out
• Distended abdomen - Pot belly appearance due to a large infestation of roundworms in the intestines
• If roundworms have traveled into the lungs, coughing and/or pneumonia may occur
• Stunted growth in puppies
• Visible worms in the dog’s vomit or stool
• Anemia
• Abdominal obstruction or rupture

Toxocara canis can be transmitted by:

• The roundworm larvae can be transmitted before birth or through the mother’s milk to the puppies
• If the dam ever had roundworms and was treated; she may still carry dormant (encysted) larvae in her tissues
• These dormant roundworm larvae can revive and pass on to her puppies 
• Dogs can become infected with Toxocara canis by ingesting feces or soil which is contaminated with larvae
• If the dog eats an infected animal (rat, mice, birds) he may contract the roundworm
• Cockroaches and earthworms may also carry roundworm larvae, which can be transmitted to the dog if they are ingested

The veterinarian will want to know the symptoms you have observed and when they started.  He may want to go over your dog’s medical history, vaccination and deworming records. The veterinarian will then perform a physical examination on your dog which could include taking the temperature, weight, and blood pressure, listening to the lungs and palpating the abdomen area.  

The vet may recommend a complete blood count and the analysis of a fecal smear. The fecal sample is then examined under a microscope and checked for roundworm eggs. The veterinarian may also choose to run a fecal flotation test.  This test mixes fecal matter with a chemical solution which is placed in a test tube and spun down in a centrifuge.  Roundworm eggs and cysts will float to the top of the test tube.

Puppies and dogs diagnosed with toxocara canis will need to be de-wormed.  Typically, the de-wormer is given over a few weeks.  The treatment goal is to kill the mature roundworms and their larvae. 

Elderly dogs and puppies with a severe infestation of Toxocara canis may need to be hospitalized.  Once hospitalized, the patient can receive 24/7 supportive care. Anemic (low red cell count) dogs may require a blood transfusion, supplements and B-12 injections.

If there are other pets in the household; they should also be treated for roundworms.

Your pet’s home and yard must also be treated for roundworms. Your dog’s kennel, bedding, blankets and toys should be cleaned with hot water and a diluted bleach solution.  The infected dog’s feces should be removed from the yard. Carpets and tile flooring should be thoroughly cleaned. If you have small children who play in the yard, the area should be professionally treated for roundworms. 

Once treated, most dogs make a full recovery from Toxocara canis.  Follow-up visits will be required to monitor the dog’s progress and to re-check a fecal sample.  Anemic and/or malnourished dogs will need a retake of a complete blood count which will help determine if the red blood cell count is back to a normal range.  

The veterinarian may recommend that the patient be placed on a monthly heartworm medication which can also help prevent and control roundworms. Dogs should be seen once a year for a wellness exam.  Puppies and elderly dogs need to be seen more often. The veterinarian can provide you with a wellness plan which is right for your dog.

It is a good precaution to pick up dog feces from the yard daily. In addition, children should wash their hands after playing in the yard. Roundworm symptoms in people include parasites in a bowel movement or coming out of the mouth or nose, stomach ache and vomiting. Please see your physician if you or your child are having these symptoms.