Echinococcosis (also known as Hydatid disease) is a parasitic disease caused by tapeworms. People become infected by ingesting parasite eggs through contaminated food, water or soil, or after direct contact with animal hosts.
Various animals act as intermediate hosts of Echinococcus as they harbour the adult worms in their intestine and evacuate the parasite eggs in their faeces. If the eggs are ingested by humans, they develop into larvae in several organs, mainly the liver and lungs, and less frequently in the bones, kidneys, spleen, muscles and central nervous system.
Both cystic and alveolar echinococcosis are characterized by asymptomatic incubation periods that can last many years until the parasite larvae evolve and trigger clinical signs. If left untreated both forms of the disease can cause serious morbidity and death. Treatment is complex and can involve surgery and anti-parasitic drugs.