The life cycle of Ascaris lumbricoides an intermediate host which is
A. cattle
B. snail
C. man
D. none of the above
The correct answer is C. man. Ascaris lumbricoides is a parasitic nematode commonly known as the giant intestinal roundworm. It primarily infects humans and completes its life cycle within their intestines. Other animals, including cattle and snails, are not intermediate hosts for Ascaris lumbricoides.
Ascaris lumbricoides is a parasitic roundworm that infects humans (option C) as the definitive host. The life cycle of Ascaris lumbricoides does not involve an intermediate host like cattle (option A) or a snail (option B). So, the correct answer is D. none of the above.
To determine the correct answer, let's break down the life cycle of Ascaris lumbricoides step by step.
Ascaris lumbricoides is a type of parasitic roundworm that infects humans. The life cycle of Ascaris involves several stages and does not require an intermediate host. Therefore, the correct answer is D. none of the above.
Here is a brief explanation of the life cycle of Ascaris lumbricoides:
1. Adult Stage: Adult female worms reside in the small intestine of a human host and produce large numbers of eggs.
2. Egg Stage: The eggs are passed out of the human host through their feces. These eggs are not infectious at this stage and require further development before becoming infective.
3. Soil Contamination: In areas with poor sanitation, the feces containing Ascaris eggs can contaminate the soil.
4. Embryonation: Over time, the eggs develop and undergo embryonation, which makes them infective. This process takes about 2 to 3 weeks, depending on the environmental conditions.
5. Ingestion: The infective eggs can be ingested by a human host if they come into contact with contaminated soil, water, or food. This commonly occurs when people consume unwashed vegetables or fruits grown in contaminated soil or drink contaminated water.
6. Larval Migration: Once the infective eggs are swallowed, they hatch in the human small intestine, releasing larvae. The larvae then penetrate the intestinal wall and enter the bloodstream, ultimately reaching the lungs.
7. Migration to the Throat: In the lungs, the larvae travel up the respiratory tract, are swallowed, and return to the small intestine.
8. Maturation: In the small intestine, the larvae mature into adult worms and mate, starting the cycle all over again.
It's important to note that Ascaris lumbricoides is a human parasite and does not require any intermediate host, such as cattle, snails, or any other animal. The human body serves as both the definitive host (where the adult worms live) and the intermediate host (where the larvae develop and migrate).
I hope this explanation clarifies the life cycle of Ascaris lumbricoides for you.