Echinococcosis is a parasitic disease transmitted from animals to humans and it is caused by the larval stage of tapeworms. Humans are most commonly infected by the accidental consumption of soil, water, or food that has been contaminated by dog or fox faeces.

There are two main forms of the disease: cystic echinococcosis (hydatid disease) and alveolar echinococcosis. Infections in humans with cystic echinococcosis are often asymptomatic, but in some cases, can cause harmful, slowly enlarging cysts in the liver, lungs, and other organs that often grow unnoticed and neglected for years.

Cases of alveolar echinococcosis in animals in areas where the disease is present are relatively common, but human cases are rare. The burden of disease in individuals with alveolar echinococcosis is much greater than cystic echinococcosis; alveolar echinococcosis is characterised by parasitic tumours in the liver, lungs, brain, and other organs, and if left untreated, can be fatal.

Both cystic and alveolar echinococcosis are often expensive and complicated to treat, sometimes requiring extensive surgery and/or prolonged drug therapy.