Echinococcus%20granulosus%20(??????)

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Echinococcus granulosus(??????)
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• GENERAL INTRODUCTION
• Worldwide distribution
• Extra-intestinal tapeworm
• Small tapeworm
• Laval infection of E. granulosus may cause
  serious clinical disease ---hydatidosis/ hydatid
  disease

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Morphology

• Only 2-8 mm long
• Usually comprises of-
• Scolex with four suckers and 2 circular rows of
  hooks
• neck
• immature proglottid
• mature proglottid
• gravid proglottid
• The eggs of E. granulosus and Teania spp. are
  indistinguishable

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• Hydatid Cyst
• Round cystic
• Wall cuticle layer, germinal layer
• Contents
• cystic fluid, brood capsules, protoscolex,
  daughter grand daughter cysts (hydatid sands)

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Hydatid cyst
Cuticle layer
Germinal layer
Daughter cyst
Granddaugher cyst
Protoscolex
Brood capsule
Brood capsule
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Hydatid cyst
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Daughter cysts
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protoscolex
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Life cycle
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• Definitive host dog other canine
• Intermediate host sheep, cattle, camel human
• Infective stage egg (gravid proglottid)
• Sites of hydatid liver, lungs, abdominal cavity,
  spleen, kidneys, heart, bones, central nervous
  system etc
• Man is a dead end host

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Adult worms in intestine of dog
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Pathogenesis

• Cause Hydatid Disease (Hydatidosis)
• Sites of hydatid cyst liver, lungs, abdominal
  cavity, spleen, kidney, heart, bones, brain etc
• Analysis of 15,289 cases in Xinjiang,China
• Liver 69.97
• Lung 19.3
• Abdominal cavity 3

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Clinical menifestations

• Depends on the size, the location and the number
  of cyst.
• Pressure by tremendous size of the cyst. results
  in disfunction of liver, lung or nervous system
• Allergy -due to rupture of cyst, may cause severe
  allergic reaction
• Regeneration due to rupture of cyst,
  intracystic protoscolex or germinal layer may be
  transplanted and result in multiple secondary
  infection
• Secondary regeneration 5.3
• Toxicosis by secretion of worm

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Surgical removal of the cysts
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Diagnosis

• History of contacting with sheep dogs
• Clinical symptoms of a slow-growing tumor
  accompanied by eosinophilia are suggestive
• Parasitological examination for finding
  scolexes, brood capsules daughter cysts
• Cysts in organs or calcified cysts can be
  visualized using x-rays, CT B-ultrasound
  examination
• Biopsy are forbidden unless during operation

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• Serological examination for specific Ab or Cag.
• Intradermal (Casoni) test with hydatid fluid is
  useful.
• Antibodies against hydatid fluid antigens have
  been detected in a sizable population of infected
  individuals by ELISA or indirect hemagglutination
  test.

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CT, brain
B-ultrasound, liver
X-ray, lung
CT, liver
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Man's arm showing positive skin test for hydatid
disease
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Epidemiology
World distribution. South America (Argentina,
Brazil, Uruguay etc ),North America (American,
Canada etc) Europe(Iceland, Russia, France, Spain
etc), Africa (Kenya, Libya, Egypt, Tunisia etc ).
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• Endemic Factors
• Contamination of the feces by infected dogs
• Intimate contact between dog, herbivorous
  animal and man in local district
• Traveling to endemic areas importing from
  endemic areas

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Control and treatment

• Regular treatment of infected dogs to reduce worm
  load.
• Prevention of dogs from eating infected offals of
  domestic animals(sheep,etc) in the endemic areas.
• Health education and strict personal hygiene.
• Avoidance of unnecessary contact with infected
  dogs.
• Surgery is still remains the mainstay of the
  treatment of hydatid disease.
• Albendazole have proved to be effective against
  hydatid cyst(for median or small size cysts).

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Summary
T. solium T. saginata E.
granulosus
Proglottides 700-1000
1000-2000 only 3
Rostellum present
absent present
Hooks 25-50
absent 24-48
Uterine branches 7-13
15-30
unregularly branched
Definitive host human
human dog/wolf
Intermediate host pig/human
cattle sheep/human
Infective stage egg/cysticercus
cysticercus egg