The disease cycle begins with an adult tapeworm infecting the intestinal tract of the definitive host. The adult tapeworm then produces eggs which are expelled in the host's feces. Intermediate hosts become infected by ingesting the eggs of the parasite. Inside the intermediate host, the eggs hatch and release tiny hooked embryos which travel in the bloodstream, eventually lodging in an organ such as the liver, lungs and/or kidneys. There, they develop into hydatid cysts. Inside these cysts grow thousands of tapeworm larvae, the next stage in the life cycle of the parasite.

Echinococcosis occurs only in the northern hemisphere, in geographically limited foci (endemic areas) of west-central Europe, Turkey, most areas of the former Soviet Union, Iran, Iraq, western and central China, and northern Japan (Hokkaido Island). If considering only at-risk rural populations in regions in central Europe that are endemic for alveolar echinococcosis, the incidence is 1-20 cases per 100,000 persons per year, despite an overall country prevalence that may be very low. In endemic foci of China, prevalence averages 5% but may reach 10% in villages with specific risk factors.

Most people with echinococcus infections are asymptomatic, especially in the lengthy early stages. Embryos are trapped in various target organs (especially the liver or lung(s); and also in muscles, bones, kidneys, brain, heart, and other organs. Embryos that are not destroyed by the body's defenses may develop into hydatid cyst(s), which grow and eventually cause pain, occlusion, or dysfunction according to the function or area of the effected organ(s). Most patients have one such cyst. The hydatid cysts form in the liver in 50-79% of patients or in the lung 20% and the remaining 10% may be found in the brain, heart, or the bones.

The presentation of human echinococcosis is protean. Patients come to the clinician's attention for different reasons, such as when a large cyst has some mechanical effect on organ function or rupture of a cyst causes acute hypersensitivity reactions. The cyst may also be discovered accidentally during radiographic examination, body scanning, surgery, or for other clinical reasons. Common chief symptoms are upper abdominal discomfort and pain, poor appetite, and a self-diagnosed mass in the abdomen. Physical findings are hepatomegaly, a palpable mass if on the surface of the liver or other organs, and abdominal distention.

Echinococcus tapeworms are parasites that infect dog species worldwide and occasionally are transmitted to humans. Infection occurs most commonly in persons who raise sheep or cattle, and who have contact with dogs. The tapeworm eggs are typically ingested during play with dogs or through consumption of garden vegetables or water contaminated by dog feces. The most common sites of tapeworm cyst formation within the body are the liver and lungs, although any internal organ or bone can be infected

Treatment in definitive hosts can be accomplished by giving canids Praziquantel or Arecoline.  Arecoline is a parasympathetic agent and increases the tonus and the mobility of smooth muscle resulting in the purgation of E. granulosus adults from the intestinal tract and passing them from the body in the mucus that follows the formed fecal material.  The drug works by paralyzing the tapeworm, resulting in its relaxing its hold on the intestinal wall.  Dosage with Arecoline is 1 tablet/10 kg. body weight but pregnant bitches and animals with cardiac abnormalities should not be treated.