Hidatid

Hidatid, more commonly referred to in medical literature as hydatid disease or echinococcosis, is a zoonotic parasitic infection caused by the larval stages of Echinococcus tapeworms, most often Echinococcus granulosus and, less commonly, Echinococcus multilocularis. Humans are accidental intermediate hosts who acquire the infection by ingesting eggs shed in the feces of infected canids, such as dogs.

After ingestion, the eggs hatch in the small intestine and the larvae migrate via the bloodstream to various organs, forming cystic lesions called hydatid cysts. The liver is affected in about two-thirds of cases, followed by the lungs; other organs including bones, brain, and kidneys may be involved. Cysts grow slowly and may remain asymptomatic for years; symptoms arise from mass effect or cyst rupture, which can trigger anaphylactic reactions or dissemination of daughter cysts.

Diagnosis relies on imaging, with ultrasound as the first-line tool and CT or MRI for detailed assessment. Serology (such as ELISA or immunoblot) can support the diagnosis but may yield false negatives, particularly for certain cyst types or locations.

Treatment is tailored to cyst size, location, and activity. Options include surgical removal, percutaneous PAIR (puncture, aspiration, injection of a scolicidal agent, and re-aspiration), or a combination of medical therapy with albendazole or mebendazole. Antiparasitic treatment may be used pre- or post-procedure or for inoperable cases, and sometimes for inactive cysts under careful follow-up.

Prevention focuses on breaking the life cycle: deworming dogs, proper disposal of offal, meat inspection, and improved hygiene in endemic regions. Hydatid disease remains a significant public health issue in pastoral and agricultural communities.