5 Questions
Where does the embryonation of Ascaris lumbricoides eggs take place?
In the soil outside the host
What is the route taken by the immature parasite after being swallowed?
It penetrates the intestinal wall and then migrates to the lungs
What is responsible for causing 'verminous' pneumonia in Ascaris lumbricoides infection?
The larva becoming stuck in an alveolar capillary
What characterizes the most intense host reactions during Ascaris lumbricoides infection?
Inflammation associated with eosinophilic infiltration of tissues
How does Ascaris lumbricoides complete its life cycle after reaching the lumen of the small intestine for a second time?
It exits through feces and starts a new life cycle
Study Notes
Ascaris lumbricoides Life Cycle
- Embryonation of Ascaris lumbricoides eggs takes place in the soil.
Migration of Immature Parasite
- After being swallowed, the immature parasite migrates through the wall of the small intestine, enters the bloodstream, and reaches the liver.
- From the liver, it migrates to the heart, and then to the lungs.
Pathology of Ascaris lumbricoides Infection
- The immature parasite's migration to the lungs causes 'verminous' pneumonia.
- The most intense host reactions occur during the lung phase of the infection, characterized by eosinophilia and inflammation.
Completion of Life Cycle
- After reaching the lumen of the small intestine for the second time, Ascaris lumbricoides matures and begins to produce eggs.
- The eggs are then excreted in the feces, and the cycle repeats.
Test your knowledge on the mode of infection of Ascaris lumbricoides, one of the largest nematodes to infect humans. Learn about the life cycle of this parasite and how it is transmitted to humans.
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