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2014-06-22 12:46:02
Cestodes Parasitology Vet Tech

Cestodes, Parasitology, Vet Tech
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  1. Dog
    Intermediate Host:
    • Dipylidium caninum packet of eggs
    • Intermediate host is the flea.
  2. Packet of Dipylidium caninum eggs. The small packets may be detected by flotation, the larger packets sink when the specimen is centrifuged.
  3. Dog
    • Eggs of Taenia pisiformis
    • Common rabbit cyst tapeworms
    • leave the host within the ripe tapeworm proglottids; however, eggs may be found during microscopic examination of feces. Individual eggs. Similiar to coccydia
  4. Cat
    Taenia taeniaeformis (cat) 4 enclosed in embryonic membranes X 410
    • A = Mesocestoides - blunt triangular shape
    • B = Dipylidium - taper at both ends (grains of rice)
    • C = Taenia - more rectangular appearance
    • A = Dipylidium
    • B = Taenia
    • C = Mesocestoides
  5. Cat
    Taenia taeniaeformis - the most common tapeworm of cats. Note serrated edge (arrow) produced by its angular shape.
  6. Anoplocephala magna in small intestine of horse
  7. Anoplocephala perfoliata at the ileocecal valve in the cecum of a yearling.
  8. Horse
    Anoplocephalan tapeworm egg from horse. Note: hooks at arrow
  9. Cow
    Similiar to:
    • Eggs of Monieza expansa
    • lrg tapeworms
    • cattle, sheep and goats. 
    • The eggs of Monieza benedeni are similar to these. X100
  10. Cow
    • Eggs of Monieza expansa 
    • Note: the pear-shaped embryo which contains 6 hooklets X410

  11. Name:
    Common name
    Packet if eggs of Thysanosoma actinoides, the "fringed tapeworm" of sheep and goats. These egg packets usually leave the host within the tapeworm segments, hence are seldom found during routine fecal examination.
  12. Sheep
    A packet containing eggs of Thysanosoma actinoides. 5 eggs are visible within the packet and one egg is free.
  13. Dog
    # of Hooklets
    Each packet contains how many eggs?
    Dipylidium caninum - each egg is provided with 6 hooklets. The only tapeworm of dog, cat and fox whose eggs are contained in packets. Each packet contains 5-20 eggs,
  14. Dog
    Taenia pisiformis - Note: radically striated shell and embryonic hooklets. The egg at the right is contained within an embryonic membrane. X400
  15. Cat
    Old Genus
    Eggs of Taenia (Hydatigera old genus) taeniaformis  - a common tapeworm. Impossible to differentiate from Taenia pisiformis of dog

  16. Name
    Name of larvae
    Intermediate host
    • 5 eggs of Echinococcus granulosus, the hydatid cyst (larvae name) tapeworm now rarely reported in dogs and cats.
    • Intermediate host = man
    • Believed to be the 2nd most zoonotic parasite- 1st is Strongyloides stercoralis
  17. Echinococcus granulosus - 3 eggs are in focus, other 2 are situated in the lower view X410
  18. Crushed Dipylidium segment released these egg packets which fill the uterus of the mature proglottids. Egg packets may be up to 500 milimicrons.
  19. Note: the radial arrangement of the Taenia eggs.
  20. Taenia eggs freshly released from the segment. They have a yolk cell around them (arrow) but this is generally digested away during the passage down the intestines.
  21. Egg of Dipylidium has a thin shell with slightly radial appearance. This is one of the few times you will see an egg out of the packet.
  22. Embryos of Mesocestoides are protected by the wall of the uterine capsule and really have no protective shell. If this capsule is ruptured the fragile looking embryos are destroyed.
  23. Dipylidium tapeworm segments on freshly passed stool. Proglottids are active when fresh but dry quickly.

  24. Anatomy
    Mature Taenia segments have a creamy mass of eggs filling branches of the uterus. Each has a single reproductive system and one lateral pore. These pores may be prominent in some species but the most common Taenia pisiformis (dog) & Taenia taeniaformis (cat) they are not noticeable.

  25. Anatomy
    Characteristically Dipylidium segments have 2 independent reproductive systems and two pores (arrow). This is a useful diagnostic feature in differentiating Dipylidium from other worms.
  26. The club shaped appearance of Mesocestoides segments are produced by the tough uterine capsule at the end of each proglottid. Unlike Taenia tapeworms, individual eggs are not released but remain inside the capsule.
    • Echinococcus are very small compared to those other tapeworms of dogs and cats (Taenias)
    • Remember the public health aspect
  27. When tapeworms are examined either fresh/hydration of dried segments the numerous __________ are useful in differentiating them from other tissues and artifacts that may be present in dog and cat feces.
    mineral granules
  28. Recovery of Echinococcus sp. by purging with arecoline. Vomiting occurs shortly followed by passage of formed feces from the lower bowels, the Echinococcus - enriched small intestine ingest and mucus.
  29. All materials are examined for _________ is hazardous . Even species preserved in formadehyde may contain viable eggs for ______.
    • Echinococcus
    • several years
  30. Dog
    Diphyllobothrium - operculated
  31. Cat
    Spirometra - cats
  32. Diphyllobothrium or Spirometra tapeworms are often passed in ribbons and each has a central pore through which the eggs are expelled.

  33. Name:
    Definitive host:
    Cittotaenia - rabbit is the definitive host
  34. Cittotaenia sp. from cat feces
  35. Cow
    Monieza sp. (dog often eats the feces of ruminant animals)
  36. Cow
    Monieza sp. egg, 3 pair of hooks are observed
  37. Horse
    Type & species:
    Other similar tapeworms:
    • Eggs of Anoplocephala mamillana
    • Nickname: small tapeworm
    • Species: horses
    • Anoplocephala magna & Anoplocephala perfoliata are similar
  38. Horse
    Eggs of Anoplocephala mamillana. The eggs enclosed a pear shaped embryo having 6 hooklets X410
  39. Horse
    Infection of Anoplocephala perfoliata with intussusception of ileum into cecum.
  40. Horse
    Hyperplasia of ileal wall associated with Anoplocephala perfoliata infection.
  41. Horse
    Cluster of the tapeworm Anoplocephala perfoliata at the ileocecal valve area of the cecum of a naturally infected horse.
  42. cow
    Name 2 common tapeworms
    • Monieza benedeni & Monieza expansa
    • Section of small intestine that has been opened to illustrate a natural infection of the tapeworm Monieza (benedeni or expansa)
  43. Tapeworms are common parasites of both cattle and sheep and are prevalent in calves and lambs during their _________________.
    first summer on pasture
  44. Dog
    • Dipylidium caninum is worldwide in distribution and common in the small intestine of the dog, cat and carnivores.
    • This slide shows numerous D. caninum on the open intestine of the dog
  45. Dog
    Dipylidium caninum - immature proglottids
  46. Dog
    Dipylidium caninum - illustrating gravid proglottids
  47. A typical Dipylidium caninum egg packet
  48. Human
    Common name
    Infects what species
    • Name: Taenia solium,
    • Common name: pork tapeworm
    • Infects: humans and swine.
    • Anatomy: Scolex with a rounded rostellum, alternating large and small hooks and four prominent suckers.
  49. Hog
    Parasite name:
    Larvae name:
    Penetrates and encysts where:
    • Parasite name: Taenia solium
    • Larvae name: Cysticerus cellulosae
    • Penetrates and encysts where: the muscular, nervous and lymphatic tissues.
    • This slide depicts muscle tissue carrying apx. 150 cystercerci per pound.
  50. The muscles of hogs may sometimes become so filled with cystericeri that the meat is known as ____________. Man usually acquires the infection by _____________.
    • "measly pork"
    • eating raw or poorly cooked pork

  51. Larval name:
    • Larval name: Cysticerus cellulosae
    • Common/Nickname: pork tapeworms 
    • Slide shows tapeworm cysts in bovine heart
  52. Cysticerus cellulosae in bovine heart
  53. Dog
    Larval name:
    Life cycle similar to:
    Intermediate host:
    Definitive host:
    • This slide shows Taenia pisiformis
    • Larval name: Cysticercus pisiformis.
    • Life cycle is similar to Taenia solium
    • Intermediate host: Rabbit
    • Definitive host: dog, cat, wolves and other carnivores
  54. Dog
    Slide shows the scolex of the Taenia pisiformis cysticerci scolex attached to the mucosa by suckers and rostellum armed with rows of hooks.
  55. Cat
    Definitive host:
    Intermediate host
    Location in intermediate host
    • Name: Taenia taeniaeformis 
    • Definitive host: domestic and wild cats Intermediate host: Rodents.
    • Location: They encapsulate themselves in the rodent's liver and produce cancer like growths. This slide depicts an adult T. taeniaeformis excised from a domestic cat.
  56. Taenia taeniaeformis in larval form (Cysticercus fasciolaris) in an infected mouse.
  57. Cat
    • Taenia taeniaeformis
    • Larval strobilocercus (cysticerci whose forebodies have begun segmentation)
  58. Dog
    Larval stage name
    • Name: Taenia hydatigena 
    • Location: found in its adult stage in the intestines
    • Species: wild dogs, coyotes and wolves. Larval Name: Cysticercus tenuicollis 
    • Nickname: thin necked bladder worm.
    • Slide show a large Taenia hydatigena cyst formation removed from muscle tissue.
  59. Sheep
    Viable and calcified cyst of Cysticercus tenuicollis attached to the rumen in bighorn sheep

  60. Name: 
    Larval Name:
    • Name: Echinococcus granulosus 
    • Larval Name:"hydatid cysts"
    • Location: liver and lungs
    • Echinococcus cysts in the liver. It is a parasite of carnivores which forms  in various organs. Eggs ingested by wild and domestic herbivores (sheep, cattle) hatch and onchosperes invade the circulatory system and lodge in various parts of the body, esp. liver and lungs.
  61. Numerous Echinococcus cysts in the lung of a sheep.
  62. Hog
    2 scoleces of Echinococcus granulosus from the liver of a 10 month old hog. Notice the hooks (arrow) present in one scolex.
  63. Camel
    • Shows a cyst in a camel lung. Notice the numerous brood capsules budding from the membrane of the thick cyst wall. 
    • Echinococcus granulosus
  64. Human
    Illustrates the fine structure of large unruptured Echinococcus granulosus cysts in a human liver.
  65. Horse
    This slide shows Anoplocephala perfoliata in a horse attached to the cecal mucosa near the ileocecal junction
  66. Anoplocephala perfoliata is a member of the family ___________ posses scoleces w/o hooks and 1 single or double female reproductive organs. The cysterceroid stage occurs in _______. ________________ are found in the intestines of horses and domestic ruminants
    • Anocephalidea
    • mites and insects
    • Anoplocephala, Monieza, and Thysanosoma
  67. Cow
    Moneiza expansa is a large tapeworm possessing 4 prominent suckers on the scolex which lacks hooks and rostellum. This slide shows Moneiza expansa scolex.
  68. cow
    Show prolottids for Moneiza expansa
  69. Pig
    This slide shows Macracanthorhynchus hirudinaceus, a common species in hogs where it occurs in the small intestine attached to the gut wall.
  70. Macracanthorhynchus hirudinaceus 
    Phylum ___________ is comprised of the "_____________" termed such because of the numerous thorn like hooks which are present on the __________.
    • Acanthocephala
    • Thorny headed worm
    • proboscis
  71. Pig
    Histological section on Macracanthorhynchus attached to a pig bowel with the insertion of the toothed proboscis inflammation and hemorrhage is visible on low power.
  72. Hog
    Gross view of an opened hog abdomen with multiple caseous nodules that were formed in response to worm attachment. Caseous means hardened pus