Echinococcus Granulosus, The Dog Tapeworm

Echinococcus granulosus is the Human tapeworm that comes from dogs, as well as, other members of the canidae family (foxes, coyotes, wolves, etc.) and cats. The dog is the definitive host and passes the eggs of the adult Echinococcus granulosus tapeworm through its stool. Sheep, cattle, goats, and humans act as the intermediate host. Once the intermediate host ingests the eggs, the eggs release the oncosphere (first-stage larvae); the oncosphere then separates and invades the intestinal wall entering the circulatory system. The oncosphere can travel throughout the body and form parasitic tumors. The most common site of tumors from the Echinococcus granulosus tapeworm is the liver (60%). These tumors, formally called Hydatid disease, are also found in the lungs (25%), brain, and other organs.

Infestation of the Echinococcus granulosus in humans is rare, but the numbers are increasing due to the trapping and transporting of wild coyotes, foxes, and wolves into the United States.