Difference between revisions of "Giardia"

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m (Text replace - 'Intestine Diarrhoea - Pathology' to 'Diarrhoea')
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{{Taxobox
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{{review}}
|name              =Giardia
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|kingdom            =Protista
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==Recognition==
|sub-kingdom        =Biciliata
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[[Image:Giardia cysts.jpg|thumb|right|150px|''Giardia'' cysts from gerbil faecea - H.D.A. Lindquist, U.S. EPA]]
|phylum            =Metamonada
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[[Image:Giardia lamblia life cycle.jpg|thumb|right|150px|''Giardia lamblia'' life cycle - Wikimedia Commons]]
|super-class        =Eopharyngea
 
|class              =Trepomonadea
 
|sub-class          =Diplozoa
 
|super-order        =
 
|order              =Giardiida
 
|sub-order          =
 
|super-family      =
 
|family            =Diplomonadidae
 
|sub-family        =
 
|genus              =Giardia
 
|species            =
 
}}
 
[[Image:Giardia lamblia life cycle.jpg|thumb|right|150px|''Giardia lamblia life cycle'' - Wikimedia Commons]]
 
 
[[Image:Giardia lamblia.jpg|thumb|right|150px|''Giardia lamblia'' - Janice Carr]]
 
[[Image:Giardia lamblia.jpg|thumb|right|150px|''Giardia lamblia'' - Janice Carr]]
 
[[Image:Giardia.jpg|thumb|right|150px|''Giardia'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Giardia.jpg|thumb|right|150px|''Giardia'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Giardia cyst.jpg|thumb|right|150px|''Giardia'' cyst - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
 
[[Image:Giardia cyst.jpg|thumb|right|150px|''Giardia'' cyst - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine]]
==Overview==
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*Flagellate protozoa
These protozoan parasite are found in humans as well as wild and domestic animals. They are a common cause of severe [[Diarrhoea|diarrhoea]] as part of the clinical symptoms [[Giardiasis|giardiasis]].
 
  
==Recognition==
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*Found in the intestine of humans
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*Associated with chronic [[Diarrhoea|diarrhoea]]
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*Found in both wild and domestic animals
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*15-20μm long
  
''Giardia spp.'' are flagellate protozoa with 8 flagella, 6 of which emerge from the body and are used in motility. They are 15-20μm long, pear shaped with a flat ventral surface. The most unique feature of this protozoa is the presence of a large adhesive disk in the flat surface that is used for attaching to the intestinal mucosa.
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*Pear-shaped
  
==Life Cycle==
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*8 flagella
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**6 flagellae are free
  
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*Large adhesive discs to hold onto intestinal mucosa
  
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==Life Cycle==
  
 
*Simple and direct
 
*Simple and direct
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***Some subspecies are zoonotic
 
***Some subspecies are zoonotic
  
{{Learning
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==Diagnosis==
|flashcards = [[Giardia_Flashcards|Giardia Flashcards]]
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|Vetstream = [https://www.vetstream.com/canis/search?s=protozoa Protozoa]
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*Faecal examination
}}
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**Cysts need to be distinguished from pollen grains and yeasts
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*Cyst excretion is intermittent
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**Faeces need to be collected over a 3 day period
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*Cysts are '''heavy'''
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**Needs higher density flotation fluids
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**Do not float well in saturated sodium chloride solution
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*Immunoassays
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**Detect cyst antigen in faeces
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==Control and Treatment==
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*Sanitation and hygiene
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**Minimise risk of human infection
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*Boil (or sterilise through other means) drinking water in regions of the world where drinking water may be contaminated
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*Avoid uncooked foodstuffs
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**Contaminated by washing
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*[[Ectoparasiticides|Drug Treatments]]
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**Metronidazole
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***Flagyl, Torgyl
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**Fenbendazole
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***Panacur
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*[[Vaccines - WikiBlood|Vaccination]]
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**Killed trophozoites
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**Available in the USA for cats and dogs
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**Decreases the excretion and viability of cysts
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**Decreases environmental pressure
  
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<big>'''[[Giardia Flashcards]]</big>
  
{{unfinished}}
 
 
[[Category:Miscellaneous_Protozoa]]
 
[[Category:Miscellaneous_Protozoa]]
[[Category:To_Do_-_Parasites]]
 

Revision as of 19:22, 6 June 2010


Recognition

Giardia cysts from gerbil faecea - H.D.A. Lindquist, U.S. EPA
Giardia lamblia life cycle - Wikimedia Commons
Giardia lamblia - Janice Carr
Giardia - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona
Giardia cyst - Courtesy of the Laboratory of Parasitology, University of Pennsylvania School of Veterinary Medicine
  • Flagellate protozoa
  • Found in the intestine of humans
  • Found in both wild and domestic animals
  • 15-20μm long
  • Pear-shaped
  • 8 flagella
    • 6 flagellae are free
  • Large adhesive discs to hold onto intestinal mucosa

Life Cycle

  • Simple and direct
  • Trophozoites attach to intestinal wall
  • Reproduce by binary fission
  • Form cysts of 10μm
    • Multi-nucleate cysts formed intermittently
    • Immediately infective when passed in faeces
  • Prepatent period of 5-6 days

Pathogenesis

  • Commonest cause of protozoal diarrhoea of man in the UK
  • Common in domesticated animals
  • Infections often asymptomatic in domestic animals
    • Can cause villous atrophy leading to malabsorption
    • Infection can persist for weeks to months if not treated

Epidemiology

  • Infection via direct oral-faecal route or through contaminated water source (water-borne)
  • Wild animals may act as a source of infection for humans
    • E.g. Beavers
  • Divided into 7 species
    • G. duodenalis most commonly infects humans
      • Some subspecies are zoonotic

Diagnosis

  • Faecal examination
    • Cysts need to be distinguished from pollen grains and yeasts
  • Cyst excretion is intermittent
    • Faeces need to be collected over a 3 day period
  • Cysts are heavy
    • Needs higher density flotation fluids
    • Do not float well in saturated sodium chloride solution
  • Immunoassays
    • Detect cyst antigen in faeces

Control and Treatment

  • Sanitation and hygiene
    • Minimise risk of human infection
  • Boil (or sterilise through other means) drinking water in regions of the world where drinking water may be contaminated
  • Avoid uncooked foodstuffs
    • Contaminated by washing
  • Vaccination
    • Killed trophozoites
    • Available in the USA for cats and dogs
    • Decreases the excretion and viability of cysts
    • Decreases environmental pressure

Giardia Flashcards