Question

Rostellum and hooks are absent in the scolex of
A. Taenia saginata
B. Taenia solium
C. Echinococcus granulosus
D. Fasciola hepatica

Answer 1

Hint:- Rostellum is defined as a protruding portion of the anterior end of tapeworms. It is a cone-like muscular configuration i.e. found on the apical end of the scolex, and in maximum species, it is armed with hooks. Rostellum consisted of several concentric rows of hooks. Hooks are referred to as the organs for attachment to the intestinal wall of the host.

Complete Answer:-
Taenia saginata is a digenetic parasite. Man is the primary host and cattle is the secondary host of Taenia saginata. It is also a Beef tapeworm. In this, the scolex is small and of pinhead size but there is the absence of rostellum and hooks on the scolex.
Taenia solium is a digenetic parasite. Man is the primary host and pig is the secondary host. In this, a minute knob-like head or scolex is present because the front-end of the body is swollen. In this rostellum, organized in two whorls with 22 to 32 curved hooks.
In the anterior region of Fasciola hepatica, the head tube is existing, whose tip possesses an oral or anterior sucker with the mouth in its centre. Under the head lobe, the ventral surface possesses a cup-shaped posterior sucker.
In Echinococcus granulosus, the dog is the primary host while sheep and goat are the intermediate hosts. Its neck is about 2-8 mm in length and possesses 3 to 4 large segments apart from Scolex.

So, the correct option is A i.e. Taenia saginata.

Note:- Fasciola hepatica is commonly referred to as Liver fluke. This fluke was discovered by Jehan de Brie but was described by Gabucinus. Echinococcus granulosus is a cat parasite but commonly known as Dog tapeworm. Taenia solium is commonly referred to as Pork tapeworm. It is distinct from its sister species because of the absence of rostellum and hooks on the scolex of Taenia saginata.