Parasite profile

Roundworms may resemble earthworms, but they’re much more dangerous, especially when they get inside a dog, or a person. The roundworm is a patient, persistent parasite that can lay up to 100,000eggs in a single day.1 Once an egg is accidentally ingested by a dog, the roundworm hatches and makes its way through the body to an ideal feeding ground, the intestine.


Dogs: Most puppies are infected with roundworms transmitted from their mothers prior to or just after birth and through nursing. Dogs and puppies can also be infected with roundworms by consuming infected animals or eggs in the environment.

Humans: It has been estimated that 14% of the people in the US are infected with roundworm larvae.Roundworms can be transmitted to people through hand-to-mouth contact with contaminated soil, sand, plants and objects such as toys and sporting equipment. Children are especially vulnerable to this type of exposure.

Clinical signs

Dogs: Roundworms live in the intestines of infected animals, depriving them of nutrients. A heavy infestation of roundworms can block the intestinal tract. Signs of roundworm infection in dogs include weight loss, diarrhea, vomiting, malnutrition and weakness. Infected puppies may have swollen abdomens, the “pot-bellied pup” look that only sounds cute, and is anything but. Roundworms may also be visible in the pet’s feces.

Humans: In people, roundworm infections can have serious and unexpected consequences. Depending on the organs to which the worms migrate, these can be serious, ranging from stomachache to pneumonia and even blindness.


Dogs: Talk with your vet about roundworms. Treating your dog with a vet-recommended product can eliminate pre-existing populations of roundworms and reduce the incidence of re-infection by these parasites. Monthly administration can reduce the risk of re-infection.  Alo by reducing the burden of roundworm eggs and hookworm larvae in your dog’s environment.

Humans: In humans, treatment usually involves medication, although in serious cases, surgery might be required.


Dogs: Ask your vet. Most heartworm preventives also kill roundworms. Be sure to ask your veterinarian for a broad-spectrum product which treats and controls multiple species of roundworms and hookworms.

Humans: People should take a conscientious approach to roundworm prevention through frequent hand washing and keeping yards and homes free of animal feces.


1. Center for Disease Control and Prevention, Division of Parasitic Diseases. Guidelines for veterinarians: prevention of zoonotic transmission of ascarids and hookworms of dogs and cats. Available at: Accessed December 16, 2009.

2. Center for Disease Control and Prevention, Division of Parasitic Diseases. New CDC study results show Toxocara infection more common than previously thought. Available at: December 16, 2009.

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