Question

Tape worm with only two or three proglottids is
a. Taenia sodium
b. Moniezia
c. Taenia saginata
d. Echinococcus

Answer 1

Hint: Tapeworms are long and flatworms with a segmented body. They live as parasites inside the intestine of many animals. The body of a tapeworm is divided into three major parts i.e. head, neck and a chain of segments known as proglottids.

Complete answer:
Platyhelminthes is a phylum of invertebrates that has a soft and simple bilaterian body structure with no specialised organs for circulation and respiration. A class in this phylum, called Cestoda, consists of parasitic worms.

Cestodes are parasitic, that means they live inside the body of other organisms (host) to survive. They have stages of growing in which the main stage is in the host (main) where they grow and reproduce. Other stages include larvae formation that occurs in other hosts. They live in the host body for years, mostly in the digestive tracts. The main host is always a vertebrate, while the other host could be a vertebrate or an invertebrate. Cestodes can be host specific where they parasite on one type of host only, or host non-specific where they parasite on a variety of hosts.

Tapeworm is a ribbon-like worm that comes under subclass Eucestoda and class Cestoda. All tapeworms have both male and female reproductive organs, and hence are hermaphrodites. The body of an adult tapeworm has a head (known as scolex), a neck region and a segmented body. These segments or units are known as proglottids. The proglottids are nothing but a container having eggs which are shed into the environment in order to infect other organisms.

Proglottids are produced in the neck region through a mode of asexual reproduction known as strobilation. The neck continuously produces these proglottids. Each proglottid has a reproductive tract and when the proglottid matures, it gets filled completely with eggs. The scolex or head has hooks or suckers, or sometimes both. Tapeworm has the ability to attach itself to the intestine of their host with the help of scolex. As they have no mouth, they absorb the nutrients from the gut of the host directly. After maturation, proglottids are shed into the environment either in the feces or moving out directly.

Echinococcus is a genus in the class Cestoda and family Taeniidae. Their body remains covered by a tegument and is divided into head (scolex), neck and 3 to 6 segments (proglottids).

Hence, the correct answer is option (D).

Note: Humans can get infection by tapeworms if they eat meat, like fish, pork, or beef, which is not cooked properly, or even if they live in poor hygienic conditions.
Different species of tapeworm have different numbers of proglottids. For example- Taenia solium has an average of 1000 proglottids and Taenia saginata has 1000 to 10,000 proglottids.