Describe the life cycle of Ascaris lumbricoides...question for 5 marks
Answers
Life Cycle:
1) The Egg – Stage 1 –
The adult ascaris worms live inside the walls of the small intestine in human beings. The female worm grows up to 35 cm in length and lays approximately 20,000 eggs that are passed out of the human stool into the environment. Unfertilized eggs are ingested but are not infective but fertilized eggs are infective and undergo further development in the next stage.
2) The Larvae – Stage – 2 –
The fertilized eggs grow into a larva. The larva then becomes infective after 18 days to several weeks, depending on the environmental conditions like warmth, moist, and soil region. After ingestion, the fertilized eggs hatch and larvae emerge and invade the intestinal mucosa. From here they transport to other parts like lungs. Then they make their way to the throat so that the worms can be swallowed and returned to the intestines so as to reach maturity.
3) The Adult – Stage 3 –
When the larvae reach the small intestine, they develop into adult worms. At this stage, the adult worm produces a large number of eggs. Around 2 to 3 months are necessary from ingestion of infective eggs to oviposition by female adult worms. Adult ascaris worms are able to live for about 1 to 2 years.
Conclusion:
Human beings are infected by these worms when they consume food or water that is contaminated by Ascaris worm eggs. Human beings and swines are primary hosts for Ascaris. Other common hosts for Ascaris include monkeys, dogs etc.
Answer:
Human bein
Explanation:
Dont know jsisjdissisksms