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Tapeworm infections of the small intestines of dogs and cats are typically caused by adult fleas when ingested by dogs or cats.  Tapeworms in dogs are less common than in the cat, probably because of their feeding habits and environmental restrictions. They represent a minority of the parasites seen in the dog but do occur regularly.  Tapeworms are often described as looking like "grains of rice". They are flat, usually ½" or shorter, and can be seen crawling out of the rectum, or moving on freshly defecated stool.  They are very itchy, and cause the pet to drag their rears on the ground to scratch. Owners find the tapeworm segments unsightly, as they crawl from the anus periodically and stick to the pet's hairs.

Life Cycle

The adult tapeworm lives in the small intestine of the dog or cat. It hooks onto the intestinal wall with its six rows of teeth to grab on with. Most people are confused about the size of a tapeworm because they only see its segments which are small; the entire tapeworm is usually 6 inches or more.  A segment carrying a sac of eggs is passed through the rectum and this is what people see.  The segment is the size of a grain of rice and is able to move. Eventually the segment will dry and look more like a sesame seed. The sac breaks and tapeworm eggs are released. These eggs are not infectious to mammals. The tapeworm must reach a specific stage of development before it can infect a mammal.

Fleas are generally hatching in this vicinity and the flea larvae do not pay close attention to what they eat and innocently consume tapeworm eggs.  As the flea progresses in its development, the tapeworm inside the flea is also progressing in development. By the time the flea is an adult, the tapeworm is ready to infect a dog or cat. The young tapeworm is only infectious to its mammal host at this stage of its development. The flea goes about its usual business, namely sucking its host’s blood, when to its horror, it is licked away by the host and swallowed.  Inside the host’s stomach, the flea’s body is digested away and the young tapeworm is released. It finds a nice spot to attach and the life cycle begins again. It takes 3 weeks from the time the flea is swallowed to the time tapeworm segments appear on the pet’s rear end or stool.

**Controlling fleas is essential to prevent recurring infections with this species of tapeworm**


There are several drugs available for the treatment of tapeworms. It is usually given once either orally or by injection under the skin. We can give this drug to kill the tapeworms, but if the fleas on the pet are not killed/removed/addressed, the pet will have tapeworms again in about another month. The tapeworm is killed and digested with the pet’s food. It is not passed in the stool later.

Only one treatment is needed to kill the tapeworms in the body; however, many clinics recommend a second treatment in three weeks. The reason for the second treatment is this: If the owner finds out at the time of their office visit that they need to control fleas to control tapeworms, they will need at least a month or so to control the fleas.

After the first treatment is given, there is no reason why the pet cannot immediately reinfect itself. It probably will reinfect itself at some point. By seeing the animal in three weeks and giving another treatment after the fleas are controlled, there is a good chance that the tapeworms will not just be back three weeks later. It takes three weeks from the time tapeworms are swallowed by the pet to the time segments can be seen by the owner.

**Controlling fleas is essential to prevent recurring infections with this species of tapeworm**


Theoretically, yes, people can get them but they must be infected the same way dogs and cats are: by swallowing an infected flea.The common tapeworms of dogs pose no threat to humans. However, Echinococcus, an uncommon tapeworm but increasing in frequency, is potentially fatal to humans. Echinococcus multilocularis is a small tapeworm that lives in the arctic fox, wolf, domestic cat and dog as the final host.  The intermediate host is the rodent; such as moles, shrews and field mice. The range of this parasite is moving south and is found in some of the northern tier states of the US. The zoonotic threat comes from the ingestion of fruit, food or water, contaminated by the feces of the fox, cat or sled dog. The increase in camping has exposed more humans and their pets to the potential of Echinococcus. Once the eggs of Echinococcus are ingested by man they form a large cyst in the liver. The only treatment is surgical removal. Unfortunately, the prognosis is guarded because the cyst itself is very fragile and can rupture with manipulation resulting in death. Treatment for Echinococcus in the dog is the same drugs used for other tapeworms.