Question

Miracidium is the larval stage of

• A. Tapeworm
• B. Roundworm
• C. Pinworm
• D. Liver fluke

Answer 1

The correct option is D

Liver fluke

The correct option is D

Explanation of correct option:

1. The body of liver flukes is flattened and leaf-like. A tegument covers the entire body. They are hermaphrodites, meaning they have both male and female reproductive systems in their bodies. They have rudimentary digestive systems and eat blood exclusively.
2. The immature eggs of the adult female liver fluke parasite are passed via the bile duct and released into the environment through feces.
3. When the eggs come into contact with water, they get embryonated and develop into miracidia larvae.

Explanation of incorrect options:

Option A:

1. The egg, one free-living larval stage, a procercoid, and a plerocercoid in the first and second intermediate hosts, respectively, and the adult in the definitive host are all part of the tapeworm's life cycle. Fish can act as a second intermediate host, a definitive host, or both in some cases.
2. Tapeworms are symmetrical on both sides (i.e., the right and left sides are similar). Some have a single lengthy segment, while others have a distinct head followed by a sequence of similar proglottid segments. Suckers and frequently hooks are seen on the scolex, which is utilized to connect to the host.

Option B:

1. The existence of a pseudocoelom, or partially formed body cavity, as well as a full digestive tract with two openings, a mouth, and an anus, distinguishes roundworms from flatworms.
2. Worm eggs transmitted from sheep in feces hatch and grow into infective larvae through the first (L1) and second (L2) larval stages (L3). The success and speed of this development are determined by climatic conditions, particularly warmth and moisture, and take at least 4 days but seldom more than 10.

Option C:

1. Pinworms are little, white worms that are 1/4 to 1/2 inch (6 to 13 millimeters) in length. Female pinworms deposit hundreds of eggs in the folds of skin surrounding the anus while the afflicted person sleeps.
2. Two to three hours after a person falls asleep, little, thin grayish-white worms may be observed around the anus. Because the worms resemble little strands of thread, they are sometimes known as threadworms.

Final answer: Miracidium is the larval stage of liver fluke.