Are Worms in Dogs Contagious?


Many dog owners worry about their pets becoming infested with worms. Understanding how worms in dogs are spread and how to protect your pet is essential because, yes worms in dogs are contagious to both other dogs and humans. Here's how to keep you and your dog safe from these intestinal parasites.

How to Prevent Intestinal Parasites in Your Dog

Because intestinal worms are dangerous for both your family and your dog, prevention is the best way to deal with them. For roundworms, hookworms, and whipworms, it is essential to maintain all dogs on effective parasite prevention medication. Talk with your veterinarian to find out which one is right or your dog. Additionally, all pregnant dogs as well as puppies should be thoroughly dewormed at appropriate intervals. To protect against tapeworms, fastidious flea control is a must for all pets in the home. Dogs should also not be allowed to ingest or play with wild animals. Environmental flea control may also be necessary to rid your house and yard of fleas.

How Do Dogs Get Worms?

In general, dogs may get intestinal worms when they come into contact with infective worm parasite eggs in the environment. However, each worm has its own unique method of transmission, so we will cover them individually.


Roundworms are both common and dangerous. The two types of roundworms that infest our pet dogs are Toxocara canis and Toxascaris leonina. Toxocara canis is the more common parasite of the two and is also the most common species to affect humans. However, both species can infest humans.

Roundworms may be transmitted between dogs in three ways. Often, puppies are born with roundworms as they become infested in utero. This can occur when the mother herself has an active roundworm infestation or from encysted, dormant cysts of roundworms in her muscles. Roundworms may also be transmitted from mother to puppy via nursing.

The final mode of transmission of roundworms in dogs occurs when they inhale or ingest infective eggs from the environment. This occurs when a dog with a roundworm infestation defecates, and the eggs are left behind on the ground.

Roundworms are especially dangerous to humans as they are a major cause of permanent blindness in people. They are also known to migrate and cause serious disease in the brain, lungs, and liver.


Hookworms live in the intestine and suck blood from their walls. If left untreated, especially in smaller dogs and puppies, hookworms may result in life-threatening anemia. Hookworms are also easily transmitted to humans.

Dogs may become infested with hookworms if they inhale or ingest either infective eggs or hookworm larvae. Hookworms are also able to burrow into the skin, so your dog may pick them up through walking or lying on the ground where the infective larvae are present. Finally, as is the case with roundworms, puppies may become infested from their mothers. Hookworms pass from the mothers to their puppies via their milk.

Humans may become infested with hookworms if they ingest or inhale the infective eggs or larvae. Humans may also get hookworms through their skin if they walk in contaminated areas without shoes.


Your dog may get whipworms, Trichuras vulpis, from ingesting infective eggs. The eggs can survive for extremely long periods of time, often up to five years, in an appropriate environment. Whipworm eggs are often found in the soil where dogs have been.

Humans may also be affected by whipworms, but it is currently unknown if the dog whipworm can establish a patent infestation in humans. Humans have their own whipworm, Trichuris trichiura, which is typically transmitted via consuming contaminated fruits and vegetables.


Tapeworms are an intestinal parasite that has a unique mode of transmission. Tapeworms require an intermediate host, meaning they have a life stage that must be completed inside a flea before they are able to become infectious. Dogs typically get tapeworms from either eating a flea found on their body or in their environment or when they ingest a small mammal or bird that was infested with fleas.

The most common tapeworm seen in dogs in the United States is Dipylidium caninum. These worms can infest humans, but due to the fact that a human must also ingest an infested flea to enable transmission, it is less common.


Despite its name, ringworm is not actually a worm but a fungal infection that can affect dogs, humans, and other animals. The condition gets its name from a ring-like appearance seen on the skin in some infections. Although this is not a worm or parasite, it can be spread between animals and humans. Ringworm is typically treated with topical and/or oral medications.