Persons with Cystic echinococcosis often remain asymptomatic until hydatid cysts containing the parasites grow large enough to cause discomfort, pain, nausea, and vomiting. The cysts grow over the course of several years before reaching maturity and the rate at which symptoms appear typically depend on the location of the cyst. The cysts are mainly found in the liver and lungs but can also appear in the brain, eyes, spleen, kidneys, heart, bone, and central nervous system. In the lungs, ruptured cyst membranes may be coughed up through the bronchi, resulting in a cure. Cyst rupture is most frequently caused by trauma and may cause mild to severe anaphylactic reactions, even death, as a result of the release of cystic fluid.

Alveolar echinococcosis is characterized by parasitic cysts in the liver and other organs including the lungs and brain. AE in humans is similar to that in the natural hosts but differs in that the larval cyst is inhibited from completing development by the host. The cysts invade and destroy surrounding tissues and cause discomfort or pain, weight loss, and malaise. AE is a dangerous disease resulting in a mortality rate between 50% and 75% and is made worse because of the remote locations and poor health care where cases are found.