Hydatid

Hydatid is a term used for a cyst produced by the larval stage of certain tapeworms in the genus Echinococcus, most commonly Echinococcus granulosus. The disease associated with these cysts is cystic echinococcosis (hydatid disease); less commonly, alveolar echinococcosis is caused by Echinococcus multilocularis. The parasite’s life cycle involves definitive hosts such as dogs or foxes that harbor adult tapeworms and shed eggs in their feces, and intermediate hosts such as sheep, cattle, or rodents, as well as humans, that ingest the eggs.

After ingestion, embryos hatch and migrate to organs where they develop into hydatid cysts. Cysts are typically located in the liver (about 60–70%) and lungs (20–30%), with other organs involved in some cases. The cysts grow slowly and may be asymptomatic for years; symptoms depend on size and location and can include abdominal pain or a palpable mass, chest symptoms, or biliary obstruction. Rupture or leakage of cyst contents can trigger anaphylaxis or lead to secondary dissemination of the parasite.

Diagnosis relies on imaging, with ultrasound commonly used and CT or MRI for extent assessment, alongside serology (such as ELISA or indirect hemagglutination) to support the diagnosis. Management depends on cyst characteristics. Active, accessible cysts are usually treated with surgery or percutaneous PAIR (puncture, aspiration, injection, re-aspiration), often combined with antiparasitic drugs like albendazole or mebendazole to reduce recurrence risk. Inactive or small cysts may be managed with observation.

Prevention focuses on interrupting transmission: regular deworming of dogs, safe slaughter practices, proper disposal of offal, good hygiene, and meat inspection in endemic areas. Prognosis improves with early detection and treatment; alveolar echinococcosis is more difficult to cure.