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Tapeworms

What are tapeworms?

Tapeworms are one of the most common intestinal parasites of dogs and cats.  There are several types of tapeworms that can affect dogs and cats, but Dipylidium caninum is the most common.  Echinococcus and Taenia are less commonly diagnosed.  Adult tapeworms live in the small intestine and can reach 8” in length.  They are composed of many small segments that break off and are passed in the stool.  Segments can also be seen attached to the skin or hair around the anus.  These segments look like pieces of rice and contain packets of eggs.  As the segments dry out, the eggs are released into the environment.  Tapeworms can be an important cause of illness, and certain types of tapeworms (Echinococcus) can also be dangerous to your family.

How did my dog or cat get tapeworms?

Tapeworms require an intermediate host to complete their life cycle.  Therefore, tapeworms are not directly infectious between dogs or cats.  In order for a dog or cat to become infected with Dipylidium, they must ingest a flea that contains tapeworm eggs.  Once the flea is digested, the tapeworms can complete their life cycle.  Less commonly, dogs and cats can become infected with Echinococcus and Taenia after eating infected rodents and rabbits.

What are the clinical signs?

While these parasites are often asymptomatic in adult dogs and cat, large numbers of worms can lead to clinical problems.  Weight loss, vomiting, diarrhea, and irritation around the anus are the most common signs in these animals.  Generally, the owners notice the segments and alert their veterinarian.

How are tapeworms diagnosed?

Tapeworms are difficult to diagnose on a routine fecal examination.  Generally, owners will notice the small segments associated with their pet’s feces or around the anus.  Echinococcus infections are harder to diagnose because the segments are small and not easily seen.  Occasionally, eggs can be visualized microscopically in the fecal sample.  Taenia and Echinococcus eggs cannot be differentiated on a routine intestinal parasite examination.

How are tapeworms treated?

Treatment is simple and effective.  A medication such as praziquantel is given which kills the adult tapeworm in the intestine.  The worm is generally digested so that it is not visible in your pet’s stool.  Generally, one treatment is effective, though if there is risk of a potential ongoing source of infection, your veterinarian may prescribe more than one treatment.  Side effects are rare with these medications.

Control of fleas is very important in the management and prevention of Dipylidium infections.  Flea control involves treatment of your pets, the indoor environment, and in some cases, the outdoor environment.  If your pet lives in a flea-infested environment, re-infection with tapeworms may occur in as little as two weeks.

How can I prevent infections?

1) All animals with potential flea exposure should have a flea preventative applied monthly.  We recommend Frontline Plus for dogs and Revolution for cats.

2) If possible, prevent ingestion of rodents and rabbits that serve as an intermediate host for these parasites.  If elimination of hunting is not possible, we recommend administering praziquantel monthly while your pet is actively engaged in hunting activities.  If feasible, control the rodent and rabbit population in your yard.

3) Prompt disposal of all feces is important, especially in yards, playgrounds, and public parks.  Litter boxes should be scooped daily and cleaned thoroughly once weekly.  A mixture of dilute bleach (1:10 dilution) can be used to clean litter boxes and contaminated toys or kennels.  Strict hygiene is essential – always wash your hands thoroughly after handling feces or cat litter.

4) All pets should have a fecal intestinal parasite examination performed at least 1-2 times per year.

Are tapeworms dangerous to humans?

Yes, tapeworms can be a health risk for humans. Echinococcus can infect humans, and the larval stages of both E. multilocularis and E. granulosus can induce severe and even fatal disease.  Humans are accidental hosts infected by the ingestion of eggs originating from dog feces.  The eggs develop into cysts in the lung, liver, brain, kidneys, or eye, and growth of the cysts can lead to severe organ damage.  In addition, rupture of the cyst can cause anaphylactic (allergic) shock and death in certain individuals.  While this is rarely diagnosed, it is a potential serious human disease.

There have been rare reports of children infected with Dipylidium after accidental ingestion of fleas.  Adequate flea control for your dog or cat and environmental management in cases of flea infestation are important.

  • Content prepared by St. Francis Animal and Bird Hospital, 1227 Larpenteur Ave. West, Roseville MN. 55113