Vital layer of Hydatid Cyst is: (DNB June 2010)
a. Echinococcosis is the most prevalent, serious human cestode infection in the world yet it is a zoonosis. Three species are responsible for 3 distinct clinical presentations, Echinococcus granulosus (cystic hydatid) and the more malignant E. multilocularis (alveolar hydatid) and E.vogeli (polycystic hydatid cyst).
b. With cystic hydatidosis from E. granulosus infection, the established larval cyst undergoes internal budding of daughter cysts that remain contained within the larger primary structure.
c. The host surrounds this cyst with a tough, fibrous capsule.
d. The primary cyst also produces a thick lamellar layer that supports a thin germinal layer of cells responsible for budding and production of thousands of juvenile-stage parasites (protoscolices) that remain attached to the wall or are free in the cyst fluid.
e. The germinal layer is thus responsible for asexual reproduction and also secretes the hydatid fluid which fills the cyst. The fluid in a healthy cyst is clear and watery.