Pseudophyllidean Cestodes Characteristics
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Pseudophyllidean Cestodes Characteristics

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Questions and Answers

What is the approximate prevalence of H. diminuta in Philippine rats?

  • 12%
  • 8% (correct)
  • 15%
  • 5%

    • Which of the following describes the ova of H. diminuta?

  • Larger than H. nana (correct)
  • Smaller than H. nana
  • Outer shell is transparent
  • Has polar filaments

    • What distinguishes the scolex of Dipylidium caninum?

  • Contains 4 deeply cupped elliptical suckers (correct)
  • Has a flat, broad shape
  • Lacks suckers altogether
  • Presence of a single row of hooks

    • Which statement about the cysticercoid of Hymenolepis diminuta is accurate?

    <p>It is similar to a cysticercus but has no bladder</p> Signup and view all the answers

    What are the genital pores of Dipylidium caninum characterized by?

    <p>Two entrances in each segment</p> Signup and view all the answers

    What is the primary characteristic of the scolex of the organism described?

    <p>It is globular with four circular suckers.</p> Signup and view all the answers

    Which of the following correctly describes the eggs contained in the gravid proglottids?

    <p>They have a thick brown striated embryophore.</p> Signup and view all the answers

    What is the mode of infection for the described organism?

    <p>Eating measly pork containing Cysticercus Cellulosae.</p> Signup and view all the answers

    In which hosts does this organism reach maturity?

    <p>Man is the final host and pigs are the intermediate host.</p> Signup and view all the answers

    Which of the following pathogenesis symptoms is associated with this organism?

    <p>Mild, non-specific abdominal complaints.</p> Signup and view all the answers

    What is the primary characteristic of mature proglottids?

    <p>Have bilateral genital pores</p> Signup and view all the answers

    What size and shape do gravid proglottids resemble?

    <p>Pumpkin seeds</p> Signup and view all the answers

    What is the treatment regimen for Hymenolepiasis in adults?

    <p>25 mg/kg body weight single dose</p> Signup and view all the answers

    Which of the following is an intermediate host for the parasites mentioned?

    <p>Human flea</p> Signup and view all the answers

    What type of symptoms are associated with Dipylidiasis?

    <p>Minimal symptoms</p> Signup and view all the answers

    What is the most serious form of cysticercosis?

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

    What is the main geographical area where Dipylidiasis is notably reported?

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

    How many eggs are typically found in each capsule within gravid proglottids?

    <p>8-15 eggs</p> Signup and view all the answers

    Which imaging techniques are used for the diagnosis of cysticercosis?

    <p>Computed Axial Tomography and Magnetic Resonance Imaging</p> Signup and view all the answers

    What is the primary method of treatment for tapeworm infections?

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

    What type of embryo is present in the ova released from the parasite?

    <p>Hexacanth embryo</p> Signup and view all the answers

    What is the significance of recovery of scolex in treatment criteria?

    <p>Confirms successful eradication of the parasite</p> Signup and view all the answers

    Which animal is primarily associated with carrying Echinococcus granulosus?

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

    What does the strobila of a tapeworm consist of?

    <p>Immature, mature, and gravid proglottids</p> Signup and view all the answers

    How are the ova of Echinococcus granulosus described?

    <p>Ovoid in shape with a hexacanth embryo</p> Signup and view all the answers

    What is the common length of adult Echinococcus granulosus worms?

    <p>3-6 mm</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the scolex of Echinococcus granulosus?

    <p>Definitive mouth structure</p> Signup and view all the answers

    What type of organism is Taenia echinococcus primarily classified as?

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

    What is a defining characteristic of Pseudophyllidean Cestodes?

    <p>They possess bothria instead of traditional suckers.</p> Signup and view all the answers

    What type of eggs do Cyclophyllidean Cestodes produce?

    <p>Spherical eggs that are bile stained.</p> Signup and view all the answers

    What is the primary mode of infection for Diphyllobothrium latum?

    <p>Ingestion of improperly cooked fish.</p> Signup and view all the answers

    What distinguishes the larvae of Pseudophyllidean Cestodes from those of Cyclophyllidean Cestodes?

    <p>Pseudophyllidean larvae have a complex life cycle with multiple hosts.</p> Signup and view all the answers

    In terms of morphology, what is true about the scolex of Cyclophyllidean Cestodes?

    <p>It may or may not have hooklets and a rostellum.</p> Signup and view all the answers

    Which organism is commonly associated with causing megaloblastic anemia in humans?

    <p>Diphyllobothrium latum.</p> Signup and view all the answers

    What is the common name for Taenia saginata?

    <p>Beef Tapeworm</p> Signup and view all the answers

    How do Pseudophyllidean Cestodes release their eggs?

    <p>By passing out mature segments in chains.</p> Signup and view all the answers

    Which of the following is the larval form that develops inside the first intermediate host for Pseudophyllidean Cestodes?

    <p>Procercoid.</p> Signup and view all the answers

    What is the defining feature of the eggs produced by the Cyclophyllidean Cestodes?

    <p>They are resistant and viable for up to 8 weeks.</p> Signup and view all the answers

    What is the length range for adult Taenia saginata?

    <p>4 to 10 meters</p> Signup and view all the answers

    Which factor is crucial for recovering the scolex after treatment for Taenia infections?

    <p>Negative stool examination three months post-treatment.</p> Signup and view all the answers

    What symptom is commonly associated with Taeniasis?

    <p>Gastrointestinal disturbances.</p> Signup and view all the answers

    Which of the following hosts is the definitive host for Taenia solium?

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

    What aspect of the uterine structure in Cyclophyllidean Cestodes differs from Pseudophyllidean Cestodes?

    <p>The uterus is convoluted and branched.</p> Signup and view all the answers

    Study Notes

    Pseudophyllidean Cestodes

    • Characterized by false grooves known as bothria.
    • Diphyllobothrium latum is a notable fish tapeworm.
    • Plerocercoid larva is infective to humans and can develop in the body.
    • Adult worms inhabit the intestine.

    Cyclophyllidean Cestodes

    • Feature round suckers called acetabula for attachment.
    • Represented by species like Taenia saginata, Taenia solium, Hymenolepis nana, and Diphylidium caninum.
    • Larval stages include various cysts such as cysticercus and hydatid cysts.
    • Eggs are operculated and require water for development into larvae.

    Morphological Differences

    • Pseudophyllidea have no branching in the uterus, whereas Cyclophyllidea have branching uterine tubes.
    • Genital pores are located ventrally in Pseudophyllidea and laterally in Cyclophyllidea.
    • Pseudophyllidea possess two slit-like grooves for attachment, while Cyclophyllidea have cup-like suckers.

    Life Cycle of Diphyllobothrium latum

    • Involves three larval stages:
      • Coracidium: Free-swimming larva ingested by copepods.
      • Procercoid: Found inside the first intermediate host (copepods).
      • Plerocercoid: Second intermediate host (freshwater fish).
    • Human infection occurs through consuming infected, undercooked fish.

    Taenia Saginata and Taenia Solium

    • Taenia saginata: Beef tapeworm, unarmed, measures 4-25 meters, with a lifespan exceeding 10 years.
    • Taenia solium: Pork tapeworm, armed with hooks; associates with more severe health issues, including cysticercosis.
    • Both species can cause taeniasis, leading to gastrointestinal disturbances.

    Egg Characteristics

    • Eggs of Diphyllobothrium latum are oval with a bile-stained appearance and granules, resistant to environmental conditions.
    • Taenia eggs are spherical and distinctively striated, infecting both pigs and humans.

    Pathogenesis and Diagnosis

    • Diphyllobothriasis can cause megaloblastic anemia from Vitamin B12 absorption.
    • Taeniasis symptoms include abdominal pain, weight loss, and pruritus ani.
    • Diagnosis involves identifying characteristic eggs and proglottids through stool examination.

    Echinococcus Granulosus

    • Known as the dog tapeworm; humans serve as accidental hosts for its cysts.
    • Transmission occurs through contact with infected canines.
    • Adult worms are small, with a specific structure of scolex, neck, and strobila.

    Comparison of Cestode Characteristics

    • Pseudophyllidea have a genuine rosette-like uterus; Cyclophyllidea have a non-rosette arrangement.
    • Genital poise positioning and reproductive strategies vary between the two orders.
    • Morphological features, like scolex structure and larval stages, highlight differences in life cycles and hosts.

    Treatment and Control

    • Praziquantel is used for treatment of both Taenia species, typically at a single high-dose regimen.
    • Control strategies focus on proper cooking of meat and maintaining hygiene to prevent zoonotic transmission.### Strobila Structure
    • Found within insects like mealworms
    • Composed of approximately 200 proglottids
    • Proglottids are narrow in shape

    Mature Proglottids

    • Contain two sets of male and female reproductive organs
    • Feature bilateral genital pores

    Gravid Proglottids

    • Resemble the size and shape of pumpkin seeds
    • Filled with capsules or packets containing 8-15 eggs, encased in embryonic membranes

    Pathogenesis

    • Associated with hymenolepiasis
    • Low worm burden in rodents; maximum recorded in humans is 19
    • Clinical manifestations are typically minimal and non-specific

    Treatment for Hymenolepiasis

    • Administered praziquantel at a dosage of 25 mg/kg body weight as a single dose

    Epidemiology

    • Found worldwide

    Ova Characteristics

    • Ova are expelled with feces alongside proglottids
    • Released through contraction of proglottids or disintegration outside the host
    • Spherical and thin-shelled, containing a hexacanth embryo

    Intermediate Hosts (1st Intermediate Host)

    • Ctenocephalides canis (dog flea)
    • Ctenocephalides felis (cat flea)
    • Pulex irritans (human flea)
    • Trichoedectes canis (dog flea)

    2nd Intermediate Host

    • Dogs serve as the second intermediate host (cysticercoid form)
    • Accidental host includes humans

    Pathogenesis for Dipylidiasis

    • Occurs rarely with multiple infections
    • Symptoms include mild intestinal discomfort, epigastric pain, diarrhea, anal pruritus, and possible allergic reactions

    Treatment for Dipylidiasis

    • Administered praziquantel at a dosage of 5-10 mg/kg body weight as a single dose

    Epidemiology for Dipylidiasis

    • Reported cases in the USA, Rhodesia, Argentina, China, and the Philippines

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    Clinical Parasitology PDF - Midterms: Cestodes

    Description

    Explore the fascinating world of Pseudophyllidean cestodes, focusing on their unique morphology and lifecycle. This quiz delves into the specific characteristics of these cestodes, including their notable features such as bothria and the life stages of Diphyllobothrium latum. Test your knowledge about these intriguing parasitic worms.

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