Schistosoma mansoni Life Cycle and Morphology
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Questions and Answers

What is a significant reaction associated with immediate hypersensitivity type 1?

  • Thrombocytopenia
  • Anemia
  • Leukopenia
  • Hypereosinophilia (correct)
  • What organ is primarily affected by verminous pneumonitis in this context?

  • Kidney
  • Stomach
  • Lung (correct)
  • Heart
  • During the migration stage of immature worms, which combination of organs is noted to have hyperplasia?

  • Liver and spleen (correct)
  • Lungs and heart
  • Pancreas and thyroid
  • Brain and kidneys
  • What time frame is associated with the migration stage of young immature worms?

    <p>4-6 weeks</p> Signup and view all the answers

    Which symptom is characteristic of the acute febrile reaction due to worm migration?

    <p>Hypereosinophilia</p> Signup and view all the answers

    What is a potential consequence of metabolic byproducts related to acute schistosomiasis?

    <p>Toxic and allergic manifestations</p> Signup and view all the answers

    When do systemic hypersensitivity reactions typically occur after schistosomiasis infection?

    <p>2-8 weeks post-infection</p> Signup and view all the answers

    What is another name for acute schistosomiasis?

    <p>Katayama fever</p> Signup and view all the answers

    Which of the following best describes acute schistosomiasis?

    <p>A systemic hypersensitivity reaction</p> Signup and view all the answers

    What is a significant factor in the pathophysiology of acute schistosomiasis?

    <p>Metabolic byproducts leading to allergic reactions</p> Signup and view all the answers

    Which morphological feature is characteristic of the adult stage of Schistosoma mansoni?

    <p>It has a distinct oral sucker.</p> Signup and view all the answers

    What is the correct sequence of the life cycle stages of Schistosoma mansoni?

    <p>Eggs → Miracidium → Cercaria → Adult</p> Signup and view all the answers

    Which stage of Schistosoma mansoni is typically free-living in the environment?

    <p>Cercaria</p> Signup and view all the answers

    In which stage does Schistosoma mansoni reproduce sexually?

    <p>Adult</p> Signup and view all the answers

    What is a key morphological feature of the cercarial stage of Schistosoma mansoni?

    <p>It has a tapered body with a tail.</p> Signup and view all the answers

    What condition is associated with massive splenomegaly due to portal hypertension?

    <p>Hypersplenism</p> Signup and view all the answers

    What is the primary cause of pancytopenia in the context of hypersplenism?

    <p>Hyperplasia of erythroid cells</p> Signup and view all the answers

    Which of the following is a consequence of congestive splenomegaly?

    <p>Decreased lymphocyte activity</p> Signup and view all the answers

    What is a potential impact on blood cells due to massive splenomegaly?

    <p>Destruction of blood cells</p> Signup and view all the answers

    Which factor contributes to the atrophy of lymphoid follicles in the spleen due to hypersplenism?

    <p>Portal hypertension</p> Signup and view all the answers

    What condition is characterized by perivascular infiltration around trapped eggs?

    <p>Granulomatous nodules</p> Signup and view all the answers

    Which pathological change can lead to the obstruction of portal blood flow?

    <p>Periportal fibrosis</p> Signup and view all the answers

    Which condition is commonly associated with portal hypertension?

    <p>Obstruction of the portal blood flow</p> Signup and view all the answers

    What type of lesions are caused by diffuse inflammation in the context described?

    <p>Diffuse inflammatory lesions</p> Signup and view all the answers

    What is likely to occur as a result of prolonged portal hypertension?

    <p>Development of collateral circulation</p> Signup and view all the answers

    Study Notes

    Schistosoma mansoni: Morphological Features

    • Cercaria: The larval stage of Schistosoma mansoni, with a tail for swimming and a penetrating spiny head.
    • Schistosomula: The larval stage that emerges after the cercaria penetrates the host's skin, without a tail, ready to migrate through the body.
    • Adult Worm (Male): Elongated, with a ventral groove that accommodates the female, often darker than the female.
    • Adult Worm (Female): Longer and thinner than the male; capable of laying thousands of eggs.

    Schistosoma mansoni: Life Cycle

    • Cercaria penetrates human skin: Infection starts with the cercaria stage, which penetrates through the skin.
    • Migration through the body: The cercaria then morphs into a schistosomula, migrating through the bloodstream to the lungs.
    • Maturation: The schistosomula continue their journey to the liver, where they mature into adult worms.
    • Mating: Once mature, the female becomes fertilized by the male and lays eggs.
    • Egg deposition in the intestinal wall: The eggs are released by the female and migrate to the intestines, eventually reaching the lumen and being excreted in feces of the human host.
    • Release of eggs: Eggs in the water develop into miracidia, which infect snails.
    • Snail infection: Miracidia multiply in snails, turning into cercariae, which can then escape and infect humans.

    Schistosoma mansoni: Migration Stage

    • Migration of young worms: Immature worms migrate through the body, causing inflammation and hypersensitivity reactions.
    • Acute febrile reaction: This migration often leads to a fever, hypereosinophilia (high eosinophil count)
    • Organ-specific inflammation: The migrating worms can target the lungs (verminous pneumonitis), liver (hyperplasia), and spleen (hyperplasia).
    • Metabolic byproducts contribute: The metabolic byproducts from the worms also provoke toxic and allergic reactions, leading to acute schistosomiasis (Katayama fever).

    Schistosomiasis: Clinical Presentation

    • Systemic hypersensitivity reaction: This condition can develop 2-8 weeks after initial infection, characterized by a strong immune response to the worms.
    • Massive splenomegaly: The spleen can become enlarged due to increased blood flow associated with portal hypertension caused by the worm infestation.
    • Pancytopenia: A decrease in all blood cell types can occur due to hyperplasia of red blood cells and atrophy of lymphoid follicles in the spleen.
    • Granulomatous nodules: Trapped eggs in the host tissue initiate an inflammatory reaction, leading to the formation of granulomatous nodules and diffuse lesions around the blood vessels.
    • Periportal fibrosis: Scarring can occur around the portal veins in the liver due to chronic inflammation, leading to a narrowing of the vessels.
    • Obstruction of portal blood flow: The scarring can obstruct the flow of blood through the portal vein, contributing to portal hypertension.

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    Description

    Discover the fascinating details of Schistosoma mansoni, including its morphological features and complex life cycle. This quiz covers the various stages from cercaria to adult worm, highlighting key characteristics and processes involved in its transmission and maturation.

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