Hydatid disease (echinococcosis) is caused by the larval forms of Echinococcus tapeworms. E. granulosus is the most frequent parasite, whereas E. multilocularis causes a more aggressive clinical disease.

Hydatid disease is caused by hydatid cysts:

• Echinococcus granulosus :
  • classic form of hydatid cyst
  • affects liver, lung, kidneys, spleen, brain, musculoskeletal system, heart

• Echinococcus multilocularis :
  • alveolar (multilocular) hydatidosis

Structural components of the hydatid cyst :

 outer acellular laminated membrane
 germinal membrane
 protoscolices, attached and budding from the membrane

Localization

 pulmonary echinococcosis (pulmonary hydatid cyst)
 hepatic echinococcosis (hepatic hydatid cyst)
 cardiac echinococcosis (cardiac hydatid cyst)

See also

 Infectious diseases

• Helminthiases