Question

Infective larvae of ancylostoma is called
(a)Rhabditiform.
(b) Second stage juvenile.
(c) Embryonated larva.
(d) Filariform larva.

Answer 1

Hint: This larva is found in the third stage of the life cycle of hookworm or ancylostoma. They are generally 500 to 700 micrometers long and have a pointed tail.

Complete answer:
The infective larvae of ancylostoma are called filariform larva. Ancylostoma is responsible for causing intestinal hookworm disease in humans. Out of two larval stages rhabditiform larvae and filariform larva, the filariform larvae is the infective one.

Additional Information: -Ancylostoma eggs are passed into the stool, and larvae hatch in one or two days when it gets a favorable condition and become a free-living organism in contaminated soil.
-This first stage larva called rhabditiform larva is released and grows in the feces or the soil or at both places.
-After 5 to 10 days the rhabditiform larvae becomes infective filariform larvae
-In favorable environmental conditions these infective larvae can survive three to four weeks.
-When the lava came into contact with the human host it penetrated the skin and carried to the heart and then to the lungs through the blood vessels.
-later the lava reached the division of the small intestine where they reside and mature into adult worms.
-These adult worms live in the lumen of the small intestine where they attach to the intestinal wall with the resultant blood loss by the host.
-Most of the adult worms are eliminated in one or two years but their longevity may reach several years also.
So, the correct answer is,’ Filariform larva’.

Note: -Ancylostoma causes the human intestinal disease so humans are called the principal host.
-It appears in two larval stages, rhabditiform and filariform.
-The filariform larvae is the infective stage that penetrates the skin of human hosts, typically bare feet.