Echinococcosis is a parasitic infection caused by the larvae of the Echinococcus species, primarily Echinococcus granulosus and Echinococcus multilocularis. These parasites typically infect the intestines of dogs and other canines, which then shed the eggs in their feces. Humans can become infected by accidentally ingesting these eggs, often through contaminated food, water, or soil. Once inside the human body, the eggs develop into cysts, usually in the liver or lungs, leading to various health issues. Symptoms may include abdominal pain, nausea, and respiratory problems, depending on the cyst's location. Treatment often involves surgery or medication to manage the infection.