Alveolar echinococcosis (AE) is characterized by parasitic tumors in the liver and may spread to other organs including the lungs and brain. In humans, the larval forms of E. multilocularis do not fully mature into cysts but cause vesicles that invade and destroy surrounding tissues and cause discomfort or pain, weight loss, and malaise. AE can cause liver failure and death because of the spread into nearby tissues and, rarely, the brain. AE is a dangerous disease resulting in a mortality rate between 50% and 75%, especially because most affected people live in remote locations and have poor health care.