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Question
A free-living roundworm which can cause serious autoinfection in human beings is_______________.
A free-living roundworm which can cause serious autoinfection in human beings is_______________.
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Solution
The correct option is A Rhabditis
- The rhabditid nematode (roundworm) Strongyloides stercoralis is the major causative agent of strongyloidiasis in humans and also a free-living autoinfective parasite.
- The life cycle of this parasite alters between two different types: a free-living cycle and a parasitic cycle. That means it can survive as both free-living and parasitic worm.
- Its parasitic life cycle begins once it is inside the host, then filariform larvae travel to the lungs through the circulatory system.
- Here they penetrate and enter the alveolar cavities, are carried up through the bronchi, the trachea, and into the pharynx (essentially the host coughs up the larvae), where they are swallowed by the host and eventually reach the small intestine.
- In the small intestine, the larvae develop into an adult female worm that produces eggs by parthenogenesis, these eggs then hatch to release rhabditiform larvae.
- These rhabditiform larvae now enter the autoinfection cycle.
- In autoinfection, the newly hatched rhabditiform larvae molt to become infective filariform larvae and later again penetrates the intestinal mucosa to enter circulation, and the same cycle is repeated.
So, the correct answer is option A.
- The rhabditid nematode (roundworm) Strongyloides stercoralis is the major causative agent of strongyloidiasis in humans and also a free-living autoinfective parasite.
- The life cycle of this parasite alters between two different types: a free-living cycle and a parasitic cycle. That means it can survive as both free-living and parasitic worm.
- Its parasitic life cycle begins once it is inside the host, then filariform larvae travel to the lungs through the circulatory system.
- Here they penetrate and enter the alveolar cavities, are carried up through the bronchi, the trachea, and into the pharynx (essentially the host coughs up the larvae), where they are swallowed by the host and eventually reach the small intestine.
- In the small intestine, the larvae develop into an adult female worm that produces eggs by parthenogenesis, these eggs then hatch to release rhabditiform larvae.
- These rhabditiform larvae now enter the autoinfection cycle.
- In autoinfection, the newly hatched rhabditiform larvae molt to become infective filariform larvae and later again penetrates the intestinal mucosa to enter circulation, and the same cycle is repeated.
So, the correct answer is option A.
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