Toxoplasma gondii Life Cycle
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Questions and Answers

What is the characteristic feature of apicomplexa parasites?

  • They are obligate intracellular parasites (correct)
  • They are obligate extracellular parasites
  • They are found only in cats
  • They have a simple life cycle
  • What is the role of the apical complex in Toxoplasma gondii?

  • It helps in digestion of host cell membrane
  • It helps in penetration of host cells (correct)
  • It helps in evasion of host immune system
  • It helps in reproduction of the parasite
  • Where does the parasite multiply sexually in the cat's body?

  • In the RES cells of the brain and eye
  • In the spleen and liver
  • Inside the intestinal epithelial lining by Gametogony (correct)
  • In the epithelial lining of the intestine
  • What is the definitive host of Toxoplasma gondii?

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

    What is the asexual form of Toxoplasma gondii?

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

    Which stage of Toxoplasma gondii is infective during transplacental infection?

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

    What is the shape of the tachyzoite?

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

    What is the mode of infection by ingesting contaminated cat feces?

    <p>Ingestion of oocysts</p> Signup and view all the answers

    Which of the following individuals are at high risk of life-threatening toxoplasmosis?

    <p>Immunologically impaired patients</p> Signup and view all the answers

    In which cells of the human body does the parasite multiply asexually?

    <p>RES cells of the spleen, liver, and lymph nodes</p> Signup and view all the answers

    What is the infective stage in organ transplantation?

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

    How many major genotypes of Toxoplasma gondii are known?

    <p>3</p> Signup and view all the answers

    What is the fate of tachyzoites in the human body?

    <p>They form tissue cysts that persist for the person's life</p> Signup and view all the answers

    What is the percentage of the population infected with Toxoplasma gondii?

    <p>1/3</p> Signup and view all the answers

    What is the definitive host in the sexual cycle of Toxoplasma gondii?

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

    What is the primary site of infection in Toxoplasma gondii infection?

    <p>Small intestine</p> Signup and view all the answers

    What is the infective stage of Toxoplasma gondii that attacks epithelial cells?

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

    Which type of blood transfusion is safe from Toxoplasma gondii infection?

    <p>Pack red-cell transfusion</p> Signup and view all the answers

    What is the type of infection that occurs when Toxoplasma gondii is transmitted from mother to fetus?

    <p>Congenital infection</p> Signup and view all the answers

    What is the characteristic of Toxoplasma gondii infection in immunocompromised patients?

    <p>It can cause reactivated infection</p> Signup and view all the answers

    What is the mode of transmission in research workers and butchers?

    <p>Contamination of mucous membrane and skin abrasion</p> Signup and view all the answers

    What is the common symptom of acquired toxoplasmosis?

    <p>All of the above</p> Signup and view all the answers

    Study Notes

    Toxoplasma Gondii

    • Intermediate hosts: humans and other mammals (e.g., sheep, cattle, pigs, birds, and mice)
    • Infective stage: all forms of T. gondii are infective to humans

    Life Cycle

    • In cat:
      • Intestinal stage: asexual multiplication by Schizogony, then sexual multiplication by Gametogony
      • Extra-intestinal stage: asexual multiplication in other body organs
    • In humans and other mammals:
      • Asexual multiplication in RES cells of spleen, liver, lymph nodes, muscles, heart, bone marrow, brain, eye, and kidney

    Mode of Infection

    • Eating raw or undercooked beef, pork, or mutton containing T. gondii cysts
    • Ingestion of oocysts in material contaminated with infected cat feces
    • Transplacental transmission during active infection
    • Blood, white cells, or platelet transfusion
    • Organ transplantation

    Phylum Apicomplexa (Sporozoa)

    • General features:
      • Obligate intracellular parasites
      • Have an apical complex to attach to and penetrate host cells
      • Complex life cycle with alternating sexual and asexual generations
    • Members of this phylum include:
      • Toxoplasma gondii
      • Plasmodium spp.
      • Babesia spp.
      • Cryptosporidium parvum
      • Isospora belli

    Toxoplasmosis

    • Geographical distribution: worldwide (except Antarctica)
    • Toxoplasma gondii attacks humans and animals (cats)
    • Three major genotypes (type I, type II, and type III) differ in pathogenicity and prevalence
    • Infects a large number of the population (perhaps 1/3), but uncommonly causes clinically significant disease
    • High-risk groups: immunologically impaired patients, fetuses, and newborns

    Morphology of Toxoplasma Gondii

    • Asexual forms:
      • Tachyzoite (trophozoite): the actively multiplying, asexual form in humans
      • Pyriform in shape with an apical complex at the pointed end

    Life Cycle of Toxoplasma Gondii

    • Development in cat intestines:
      • Sporulated oocyst
      • Sporozoites and bradyzoites attack epithelial cells
    • Development in human intestine:
      • Unsporulated oocyst passes in stool of the cat
      • Sporulated oocyst infects humans

    Pathogenesis and Clinical Picture of Toxoplasmosis

    • Toxoplasmosis is considered an opportunistic infection
    • Acquired infection: acquired toxoplasmosis
    • Congenital infection: congenital toxoplasmosis
    • Recrudescence in immunocompromised patients

    Symptoms of Acquired Toxoplasmosis

    • Depends on immune status and age of infected person, virulence of infecting strain
    • Most cases are asymptomatic
    • Mild form: lymphadenopathy, myalgia, low irregular fever, slight anemia with lymphocytosis, fatigue

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    Toxoplasmosis PDF

    Description

    Learn about the life cycle of Toxoplasma gondii, a parasitic protozoan, including its intermediate hosts, infective stages, and habitat in cats and other mammals.

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