Hydatidosis or cyst hydatic disease is a cosmopolitan larval cestodosis caused principally by the <i>Echinococcus granulosus</i> tapeworm, the adult form of which parasitises the intestine of dogs. Hydatidosis generally affects large domestic herbivores; humans are dead-end hosts, infected through contact with herding dogs or through ingestion of food contaminated with canine excrement.

A granulomatous inflammation leading to multiple granuloma formation, which is a specific type of inflammation. A granuloma is a focal compact collection of inflammatory cells, mononuclear cells predominating, usually as a result of the persistence of a non-degradable product and of active cell mediated hypersensitivity.