Echinococcus Granulosus

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Echinococcus Granulosus

• Reba Cunningham

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Echinococcus Granulosus

• Common Name Tapeworm
• Also Called Hydatid Worm
• About 5mm long

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Intermediate Hosts

• Any organism that ingests dog feces
• Herbivores, Hoofed Animals, Livestock and Humans
• Examples Sheep, Deer, Moose, Wallabies, Camels,
  Pigs and Kangaroos

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Definitive Hosts

• Wild Canids Such as Dogs, Wolves and Coyotes

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Transmission

• Ingestion from contaminated grass, usually for
  herbivores
• Contamination caused by poor hygiene, followed by
  transfer to the mouth
• Accidental ingestion of contaminated soil,
  berries or vegetables

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Morphology

• Larvae?
• Metacestode or Hydatid
• Spherical and filled with fluid
• Outer layer supports the cyst
• Nucleated germinal layer has developing brood
  capsules which break off and float freely in the
  fluid
• Protoscolices form within the brood capsules,
  which rupture to give free protoscolices in the
  fluid
• Cysts about 20cm in diameter

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Morphology Continued

• Adult?
• Consist of 3 proglotids Immature, Mature and
  Gravid proglotid
• Scolex has a rostellum with a double row of 30-36
  hooks

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Protoscolices
Scolex With Hooks
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Life Cycle
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Symptoms

• Usually no symptoms for dogs but if highly
  infected, the intestinal wall may become inflamed
• In humans symptoms may include liver enlargement,
  jaundice, abdominal pain, weight loss, fever and
  anaphylactic shock when the immune system reacts
  to ruptured cysts

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Where Is It Found?

• Occurs practically worldwide
• North America, South America, Europe, North
  Africa, the Middle East, and in South-Central and
  East Asia

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Diagnosis

• Fecal float to recover eggs
• Ultrasonography and other imaging techniques
  along with serological tests

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Treatment

• Most common treatment is surgery but it is not
  100 effective
• Albendazole is used to prevent the cyst from
  recurring
• Keeps the worm from absorbing glucose, the worm
  loses energy and dies

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Additional Info

• http//www.dpd.cdc.gov/dpdx/HTML/Echinococcosis.ht
  m