Understanding Tapeworms

What Are Tapeworms?

Tapeworms are parasites that live in the small intestines of many different species of animals, including humans. 

Depending on the species, these tapeworms can vary greatly in length. For example, Echinococcus multilocularis is less than 1 cm long, whereas an adult Taenia saginata may be up to 10 metres long! Except for the head, a tapeworm’s body is made up entirely of small segments, called proglottids, which break off from the end of the worm’s tail as it grows and contain the parasite’s eggs. Both intact proglottids (which can move by themselves) and eggs may be passed in the feces.

Of all the tapeworms in pets, Echinococcus spp. pose the greatest disease risk to people.

Different Tapeworms, Different Risks

There are three main groups of tapeworms, each containing one or more species, that are a concern for most domestic animals and humans. Each group poses a different level of risk to people, and may be spread between animals and people in a different ways.

How do I know if my pet has tapeworms?

Tapeworm infection in adult animals rarely causes illness, even with large numbers of worms, but the motile proglottids may cause irritation around the anus, causing the animal to chew or rub the area or “scoot“. Your veterinarian can perform a fecal “float” on your pet to look for eggs of tapeworms (and
other parasites) in the feces. It is important to have this done regularly. It is impossible to tell Echinococcus eggs from the eggs of Taenia tapeworms based on
a fecal float. The intact proglottids (egg sacs) of Echinococcus are distinguishable from Taenia, but they are very small and extremely difficult to find.

Pets infected with Echinococcus may not pass tapeworm eggs in every fecal sample, so even if the fecal test is negative, it is still important to pick up after your pet and use good hygiene when handling your pet’s feces, especially if you live in an area where Echinoccoccus is endemic.

How are tapeworm infections treated?

In pets, intestinal tapeworm infections are easily treated using oral dewormers such as praziquantel. Nonetheless, if your pet needs to be treated for tapeworms, it is important to also take steps to prevent your pet from being reinfected afterwards. Pets may shed very high numbers of parasite eggs for a few days after being treated, so be particularly diligent about removing pet feces promptly and hand washing.

People with intestinal tapeworm infections are typically treated the same way as pets (using an oral dewormer).

How can I prevent tapeworm infection in me, my pets & my family?

The two major components of preventing tapeworm infection in people are preventing intestinal infection in pets and preventing human exposure to the parasite eggs and cysts.

Have your veterinarian check your pet’s feces at least once a year to detect parasite eggs. In areas where Echinococcus has been recently reported, it’s best to do this several times per year. Because pets may not pass tapeworm eggs in every fecal sample, testing three fecal samples collected over the course of a week is recommended to decrease the likelihood of a false-negative test.

Flea control is essential for preventing D. caninum infection in pets, because without adult fleas the parasite cannot be transmitted. Remember that pets can be exposed to fleas from other animals if they go outside, even if they don’t become infested themselves. Do not allow pets to hunt or scavenge other animals. Keep cats indoors and prevent rodent infestations in the house. Keep dogs on a leash or at least in sight when outdoors. Do not allow hunting dogs to eat raw offal. Ensure all meat or other animal-based products are properly cooked before being fed to pets, especially if the animal source is from an area where Echinococcus is endemic.

Meat for human consumption should also always be thoroughly cooked to reduce the risk of transmission of a variety of parasites and bacteria, including tapeworms. Pick up pet feces promptly and wash you hands thoroughly afterwards.

If working with soil, especially in an area where the soil may be contaminated by feces from foxes, feral dogs or similar animals, always wear gloves and wash hands thoroughly when done.