Echinococcus granulosus

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Echinococcus granulosus
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Echinococcus granulosus

• Hydatid disease
• Cosmopolitan
• Mediterranean countries
• Russian federation
• China
• North and East Africa
• Australia
• South America
• North America Deep South and Far West

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Echinococcus granulosus

• ADULT MORPHOLOGY - small tapeworm - 3-6 mm long
• consists of scolex, neck, immature proglottid,
  mature proglottid, and gravid proglottid
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Carnivore
Humans
Herbivore
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10-30 scolices per brood capsule
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Pathogenesis

• Hydatid cyst
• Slow growth
• Asymptomatic for years
• Up to 20 years (unless in nervous system)
• Pathology depends on
• Location
• Size
• How many

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Pathogenesis

• Crowds host tissues
• Destroys tissues-replaces with cyst
• Grows continuously
• 15 quarts of fluid
• Millions of scolices
• Rupture of the cyst fatal
• Anaphylactic shock hydatid fluid (death)
• In most herbivores, cysts do not keep growing

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Unilocular hydatid cyst in the lung Note
pressure effects exerted by cyst that crowds and
destroys lung tissue
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Hydatid Cyst
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Diagnosis

• Physical imaging
• MRI
• CT scan
• Ultrasound
• X-ray
• Serodiagnosis

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Hydatid Cyst of Echinococcus granulosus
 
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Treatment

• Surgery
• Preoperative chemotherapy-albendazole
• Protoscolicidal compounds
• Ethanol
• Saline
• Formalin
• Recurrence
• 50
• Undetected cysts
• Inadequate removal
• Mebendazole
• 48 of cysts

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Epidemiology

• How do people get infected?
• How do eggs get into environment?
• How do we ingest them?

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Epidemiology

• Human-Dog
• Herbivores Sheep, goats, camels, rabbit
• Sheep raising areas
• Offal

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Epidemiology

• Human-Dog contact

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Epidemiology

• Human-wildlife contact

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Echinococcus granulosus
 
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Complex

• Echinococcus granulosus comprises multiple
  species
• Life cycle patterns
• Host specificity
• Development Rate
• Antigenicity
• Transmission dynamics
• Chemotheraputic drug response
• Pathology

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Control

• Sheep vaccine successful

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Echinococcus multilocularis
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Life Cycle of Echinococcus multilocularis

• 1. Adult tapeworm occurs in intestine of foxes.
• Dogs, cats, and coyotes can also serve as
  definitive hosts.
• Adult is small - 1-2 mm long

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Echinococcus multilocularis


Alveolar hydatid cyst in a mouse - cyst
metastasizes from the liver to fill the body
cavity
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Alveolar Hydatid Cyst
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Echinococcus multilocularis

• Liver
• Cyst multilocular hydatid
• External budding
• Extend processes throughout tissues
• Cirrhosis of liver
• Thinner membrane
• Metastasis
• Advanced cases

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Echinococcus multilocularis

• Not easily operable
• timing
• Chemotherapy
• Praziquantel can increase growth
• Mebendazole and albendazole given throughout the
  life of the patient.
• retards growth
• Not easily treatable

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Echinococcus multilocularis

• Fox tapeworm
• Europe, Asia, Americas, New Zealand

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Echinococcus multilocularis
This species has recently been reported in the
upper Midwest (North and South Dakota, Minnesota,
Iowa, Nebraska, southern Wisconsin, and Indiana).
Recently identified in Illinois, Ohio and
Missouri.
   
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Epidemiology

• Increasing in Europe
• Up to 1980s only in France, Switzerland,
  Germany, and Austria
• Spreading throughout Europe.

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Epidemiology

• Increase in fox infection
• Increase in human infection
• Still rare
• Switzerland and Germany
• Antirabies vaccines
• Increased fox abundance
• Movement of foxes
• Encroachment on urban areas
• Contact with domestic dogs

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Hymenolepis
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Hymenolepis

• Hymenolepis diminuta
• Rare in humans
• 90 cm
• Model tapeworm
• Hymenolepis nana
• Dwarf tapeworm 40 mm long
• Common in humans
• 97.3 children in Moscow
• 1 children in SE US

Cysticercoid
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Hymenolepis nana
D
A
1
B
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3
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C
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Pathogenesis and Treatment

• Similar to Adult species of Taenia
• Praziquantel

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Dipylidium caninum
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Dipylidium caninum

• Most common tapeworm of dogs
• Cats, humans
• 2 sets of reproductive organs

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Gravid proglottids shed
Dog eats flea
Infective stage?
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Diagnostics
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Pathogenesis and Treatment

• Similar to Adult species of Taenia
• Praziquantel