Dog Worm Species

In dogs, there are two different types of worms: roundworms and tapeworms and there are three types of nematodes: roundworms, hookworms, and whipworms.



Roundworms in dogs look like spaghetti strands and they can about 9 to 17 cm long. Young dogs are more susceptible and symptoms are more noticeable, but in adults, the infection is barely noticeable.

Infection occurs because your dog is in places where there are worm eggs and are contracted from sniffing, fur, or paws. The eggs hatches in the dog into the gastrointestinal tract and develop into worm larvae; they can penetrate the intestinal wall and create intestinal issues within the body.


In pregnant dogs, the larvae migrate to the mammary tissue, where they infect the puppies through the milk. Even before birth, the puppies can still be infected by the uterus. 3 to 4 weeks later, these roundworms grow in the intestine of the puppy. Adult roundworms lay about 200,000 eggs per day. So they contaminate the environment at a high rate. Practically all young dogs are infected with roundworms and about 20-30% of all adult dogs.


Usually, you will not notice anything when your dog is infected with roundworms unless the infection is severe, and puppies can potentially die immediately after birth. From the 2nd and 3rd week you can see worms in the feces, in very serious infections can even regurgitate worms.

When infected there is a reduced resistance to disease, and sometimes diarrhea or constipation can be observed.  Typical young dogs appear to have large bellies and a dull coat. These dogs are obviously a major source of infection for their surrounding peers, but also to you.


In humans, roundworm eggs cannot mature into worms, but the larvae bore through the intestinal wall and spread through the bloodstream in the human body, where they cause inflammation of the organs, eyes, and brains can be so affected. Teach your children to wash their hands before they eat after being around your dog.



Hookworms are tens of times smaller than the roundworm, 5-18mm. The worm enters the dog through the skin inward than through the bloodstream to reach the intestine and grow three weeks to adult hookworm. Dogs can also be infected through breast milk, eating grass, soil or contaminated feces. Hookworms cause serious damage because they feed on intestinal cells or blood. Infected animals show disease symptoms such as anemia, diarrhea, lethargy and a dull coat.



A dog can be infected with whipworm (4-7.5 cm) by licking mature worm eggs from feces of infected dogs or foxes. They pierce deep into the mucous membrane of the large intestine, causing watery diarrhea with traces of fresh blood. This worm infection does not occur before the age of 2 to 3 months and is often noticed after staying at a kennel.



Tapeworms also live in the gut of your pet and can be up to several millimeters to several meters. They consist of a head, a neck and a large number of links that are filled with dozens of tapeworm eggs.

The tapeworm links look like a kind of rice grain in the droppings and the hair of the dog. The links, are filled with eggs and are eaten by another animal “intermediate host” in which the eggs develop into larvae tapeworm.  The tapeworm larvae then release into the intestine and develop into adult tapeworms. Examples of intermediate hosts for dogs include flea and rabbits.

Infected dogs lose weight and have a dull coat. They are also more susceptible to disease.

The tapeworm transmitted by fleas is infectious to humans, but not dangerous. After accidental ingestion of a flea, small adult tapeworms can develop in the intestine of humans and thus cause mild abdominal discomfort.

Elsewhere in the world, a kind of tapeworm of just a few millimeters long forms, also called the fox tapeworm, is a real danger to humans. These tapeworms cause cysts or tumors in vital organs like the liver and lungs of humans. Infection occurs through contact with infected animals (dogs, foxes or cats) or by eating tainted blueberries.