Question

Size of common roundworm or Ascaris lumbricoides is
A. 15 – 30 cm in male and 20 – 40 cm in female
B. 10 – 15 cm in male and 15 – 25 cm in female
C. 5 – 10 cm in male and 10 – 15 cm in female
D. 3 – 5 cm in male and 7 – 10 cm in female

Answer 1

Hint: Ascaris lumbricoides is the most common parasite found in humans. It is commonly called large roundworm in humans that grows upto 35cm long. It is a nematode that belongs to phylum nematoda.

Complete Answer:
- The larva and adult roundworm are cylindrical and bisexual worms. The characteristic feature of ascaris is its great size. In diameter, the male roundworms are 2 - 4 mm or 0.08 - 0.2in wide and 15 - 31 cm or 5.9–12 in long.
- The male has a blunt pointed tail. Its posterior end is curved ventrally. The female roundworms are about 3 – 6 mm or 0.1–0.2 in diameter and 20–49 cm or 7.9–19 in long. The vulva covers about one third of the length of the body and is located at the anterior end.

Therefore the correct answer is (A) 15 – 30 cm in male and 20 – 40 cm in female.

Note: Ascaris lumbricoides is widely known for causing the disease Ascariasis in humans and are located in the small intestine. They are a group of helminths. It is estimated that about one sixth of the human population is infected by Ascaris or other types of roundworm. Based on recent studies, it has been proposed that Ascaris lumbricoides (large human roundworm) and Ascaris suum (pig roundworm) are of the same species.