Difference between revisions of "Giardia"

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{{Taxobox
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{{review}}
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|name              =Giardia
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|kingdom            =Protista
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{{toplink
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|sub-kingdom        =Biciliata
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|backcolour =
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|phylum            =Metamonada
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|linkpage =Parasites
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|super-class        =Eopharyngea
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|linktext =PARASITES
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|class              =Trepomonadea
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|pagetype=Bugs
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|sub-class          =Diplozoa
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|sublink1=Protozoa
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|super-order        =
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|subtext1=PROTOZOA
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|order              =Giardiida
 
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|sub-order          =
 
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|super-family      =
 
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|family            =Diplomonadidae
 
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|sub-family        =
 
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|genus              =Giardia
 
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|species            =
 
 
}}
 
}}
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[[Image:Giardia lamblia life cycle.jpg|thumb|right|150px|''Giardia lamblia life cycle'' - Wikimedia Commons]]
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<br>
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==Recognition==
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[[Image:Giardia cysts.jpg|thumb|right|150px|''Giardia'' cysts from gerbil faecea - H.D.A. Lindquist, U.S. EPA]]
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[[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]]
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==Overview==
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*Flagellate protozoa
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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]].
 
  
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==Recognition==
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*Found in the intestine of humans
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*Associated with chronic [[Intestine Diarrhoea - Pathology|diarrhoea]]
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*Found in both wild and domestic animals
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*15-20μm long
  
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''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
  
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==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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==Pathogenesis==
 
==Pathogenesis==
  
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*Commonest cause of protozoal [[Diarrhoea|diarrhoea]] of man in the UK
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*Commonest cause of protozoal [[Intestine Diarrhoea - Pathology|diarrhoea]] of man in the UK
  
 
*Common in domesticated animals
 
*Common in domesticated animals
  
 
*Infections often asymptomatic in domestic animals
 
*Infections often asymptomatic in domestic animals
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**Can cause villous atrophy leading to malabsorption
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**Can cause cillous atrophy leading to malabsorption
 
**Infection can persist for weeks to months if not treated
 
**Infection can persist for weeks to months if not treated
  
 
==Epidemiology==
 
==Epidemiology==
  
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*Infection via direct oral-faecal route or through contaminated water source (water-borne)
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*Infection via direct oral-faecal route or through contaminated water source (water-bourne)
  
 
*Wild animals may act as a source of infection for humans
 
*Wild animals may act as a source of infection for humans
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***Some subspecies are zoonotic
 
***Some subspecies are zoonotic
  
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{{Learning
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==Diagnosis==
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|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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}}
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**Cysts need to be distinguished from pollen grains and yeasts
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*Cysts 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 floatation fluids
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**Do not float well in saturated sodium chloride solution
 +
 
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*Immunoassays
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**Detecting 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 contmainated
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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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{{unfinished}}
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*[[Vaccines - WikiBlood|Vaccination]]
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[[Category:Miscellaneous_Protozoa]]
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**Killed trophozoites
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[[Category:To_Do_-_Parasites]]
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**Availbale 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

Revision as of 14:51, 21 December 2008

 This article has been peer reviewed but is awaiting expert review. If you would like to help with this, please see more information about expert reviewing.


Infectious agents and parasitesWikiBugs Banner.png
PARASITES
PROTOZOA



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 cillous 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-bourne)
  • 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
  • Cysts excretion is intermittent
    • Faeces need to be collected over a 3 day period
  • Cysts are heavy
    • Needs higher density floatation fluids
    • Do not float well in saturated sodium chloride solution
  • Immunoassays
    • Detecting 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 contmainated
  • Avoid uncooked foodstuffs
    • Contaminated by washing
  • Vaccination
    • Killed trophozoites
    • Availbale in the USA for cats and dogs
    • Decreases the excretion and viability of cysts
    • Decreases environmental pressure
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