Hymenolepis Diminuta Parasitology Quiz
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Questions and Answers

Which of the following statements about the morphology of Hymenolepis nana is correct?

  • The eggs are barrel-shaped with outer and inner shells and transparent polar prominences. (correct)
  • The male has a caudal extremity coiled 360 degrees.
  • The female is smaller than the male.
  • The anterior part is shorter and thicker than the posterior part.

    • What is the primary pathogenic effect caused by Hymenolepis nana?

  • Rectal prolapse and edematous rectal tissue.
  • Inflammation of the colon with hemorrhage.
  • Portions of worms embedded in the rectum.
  • All of the above. (correct)

    • Which of the following statements about the morphology of Hymenolepis nana is incorrect?

  • The male has a caudal extremity coiled 360 degrees. (correct)
  • The female has a bluntly rounded posterior part.
  • The anterior part is long and slender.
  • The posterior part is shorter and much thicker.

    • Which of the following is not a characteristic of the eggs of Hymenolepis nana?

    <p>Bluntly rounded ends.</p> Signup and view all the answers

    What is not a feature of the pathogenesis of Hymenolepis nana?

    <p>Blood loss leading to anemia and protein loss.</p> Signup and view all the answers

    What is the most common method for diagnosing Fasciola hepatica infection?

    <p>Fecal examination for eggs or proglottids</p> Signup and view all the answers

    Which of the following is the recommended treatment for Fasciola hepatica infection?

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

    Which of the following is NOT a potential pathological effect of Fasciola hepatica infection?

    <p>Hydatid cysts in the brain</p> Signup and view all the answers

    Which of the following is NOT an intermediate host for Fasciola hepatica?

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

    What is the infective stage of Fasciola hepatica that leads to human infection?

    <p>Metacercariae from aquatic vegetation</p> Signup and view all the answers

    Which of the following statements about the life cycle of Fasciola hepatica is correct?

    <p>The larvae migrate to the liver and develop into adults</p> Signup and view all the answers

    What is a characteristic feature of the morphology of the adult Fasciola hepatica?

    <p>Scolex with a pair of suctorial grooves (bothria)</p> Signup and view all the answers

    Which of the following statements about the pathology of Fasciola hepatica infection is incorrect?

    <p>It can result in the formation of hydatid cysts in the brain</p> Signup and view all the answers

    What is a recommended prevention measure for Fasciola hepatica infection?

    <p>Thorough cooking of freshwater fishes and aquatic vegetation</p> Signup and view all the answers

    Which of the following statements about the life cycle of Fasciola hepatica is incorrect?

    <p>Eggs are ingested by the intermediate host</p> Signup and view all the answers

    Study Notes

    Egg Morphology and Clinical Manifestations

    • Egg morphology: barrel-shaped, outer and inner shell, transparent polar prominences (polar plugs)
    • Clinical manifestations: headache, abdominal pain, dizziness, diarrhea, enteritis due to necrosis of intestinal epithelial cells

    Hymenolepis diminuta (Rat Tapeworm)

    • Hosts: rats, mice, and other rodents
    • Life cycle: ingestion of intermediate host, grain weevil, containing larval stages
    • Infests: dried grains, fruits, flour, and cereal
    • Morphology: larger than H. nana, scolex with no hooks, eggs with no polar filaments
    • Pathology: minimal and non-specific
    • Treatment: Praziquantel

    Taenia spp. (Tapeworms)

    • Two species that infect humans: Taenia saginata and Taenia solium
    • Life cycle: infective egg from human feces ingested by cow or pig, oncosphere hatches and penetrates the intestinal mucosa, localizes and encysts in muscle
    • Morphology: scolex attaches to human intestine, larva: cysticercus, fluid-filled barrier with an invaginated scolex, eggs of both species are identical

    Taenia saginata (Beef Tapeworm)

    • MOI: ingestion of cysticercus in cow flesh
    • Cysticercus: ovoidal, milky white in color, single scolex invaginated into a fluid-filled barrier
    • Morphology:
      • Scolex: unarmed with 4 sucking disks
      • Gravid proglottids: 1 inch or slightly longer, uterus contains 15-20 primary branches, uterine pore located in a lateral position
      • Eggs: identical to T. solium, unsegmented region, high regenerative capacity
    • Diagnosis: identify proglottids, eggs, or scolex, perianal swabs, eggs can be differentiated

    Hymenolepis nana (Dwarf Tapeworm)

    • Most common tapeworm infection in humans
    • Definitive host: humans, rodents
    • Life cycle: ingestion of embryonated eggs or insects (beetles, fleas) containing larvae, autoinfection: eggs remain in the intestine
    • Diagnosis: finding eggs in feces
    • Morphology:
      • Scolex: 4 sucking disks, short rostellum with hooks
      • Proglottid: broader than long, rarely seen in feces specimens
      • Body divided into two parts: anterior (long and slender) and posterior (shorter and thicker)

    Hookworms (Blood-sucking Nematodes)

    • Morphology: large plates in the mouth, adults with large, cylindrical, fusiform bodies, females larger than males
    • Pathology: blood loss, anemia, protein loss, rectal prolapse, edematous rectal tissue, inflammation of the colon with hemorrhage

    Necator americanus (Hookworm)

    • Adults: small, cylindrical, fusiform, gray, females larger than males
    • Copulatory bursa: catch, hold female, pair of ventral cutting plates

    Ancylostoma duodenale (Hookworm)

    • Slightly larger than N. americanus
    • Head continuous in the same direction as body curvature
    • Two pairs of curved ventral cutting teeth

    Metabolism of Ascaris spp.

    • Embryos: consume lipid and carbohydrate reserves during first 10 days of development, resynthesize carbohydrate from fat
    • Snails: Lymnaea, aquatic plants: Nasturtium officinale (watercress), Ipomea obscura, Ipomea aquatica (kangkong)

    Clonorchis sinensis (Chinese Liver Fluke)

    • Bile duct and gallbladder of humans and fish-eating mammals (dogs, cats)
    • Found in China, Korea, and Japan
    • Egg morphology: small protuberance at the abopercular end, ovoid, yellowish to brown in color
    • Mode of transmission: ingestion of metacercariae, excysts in the duodenum, attaches to mucosa of bile duct, pancreatic duct, and gallbladder through suckers and embedding in sticky mucus

    Fasciola spp. (Liver Flukes)

    • Liver and biliary passages of humans and herbivorous mammals (ruminants)
    • Mode of transmission: ingestion of metacercariae encysted from edible aquatic plants or by drinking water with floating metacercariae
    • Intermediate hosts: snails (Bulimus striatulus, Parafossarulus genera, Thiara granifera, Melanoides tuberculatus)
    • Pathology: migrate by penetrating intestinal wall, peri cavity, abdominal wall, diaphragm, and lungs, immature worms settle close to the bronchi, grow, and sexually mature
    • Clinical manifestations: granulomatous reaction in the lungs, development of fibrotic encapsulation, pairs of adult worms found in fibrotic capsules or cysts in lungs of infected hosts, chest pain, hemoptysis, myalgia, dyspnea, fever, fatigue

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    Description

    Test your knowledge on Hymenolepis diminuta, a rat tapeworm that infests rodents and can cause enteritis in heavy infections in humans. Learn about its life cycle, clinical manifestations, pathology, morphology, and treatment with Praziquantel.

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