Difference between revisions of "Anoplocephala"

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{{Taxobox
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|name              = ''Anoplocephala
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== ''Anoplocephala'' Species ==
|kingdom            =
 
|phylum            =
 
|class              = ''Cestoda
 
|sub-class          =
 
|order              =
 
|super-family      =
 
|family            = ''[[Anoplocephalidae]]
 
|sub-family        =
 
|genus              =
 
|species            =
 
}}
 
==Introduction==
 
 
[[Image:Anoplocephala.jpg|thumb|right|150px|''Anoplocephala'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 
[[Image:Anoplocephala.jpg|thumb|right|150px|''Anoplocephala'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
''Anoplocephala'' is from the family [[:Category:Anoplocephalidae|''Anoplocephalidae'']].  Several species of ''Anoplocephala'' occur in equidae, but ''A. perfoliata'' is the only common species in the UK.  It is an equine cestode, more commonly known as a tapeworm.  It is currently commonly seen in horses within the UK, usually affecting younger horses.
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Several species of ''Anoplocephala'' occur in equidae, but ''A. perfoliata'' is the only common species in the UK.
 
 
==Identification==
 
Superficially, ''A. perfoliata'' looks more like a [[:Category:Trematodes|trematode]] than a tapeworm, but closer inspection reveals that the body compromises many '''segments''' that are wide, but very short. These parasites have no hooks, but do have '''large suckers''' that allow the parasite to attach to the mucosal surface.  An adult may be 4-8cm in length. 
 
The gravid segment contains characteristic eggs with a ‘rounded triangular’ shape, which are around 70μm long.  The '''oncosphere''' is contained in the ‘pyriform apparatus’ (a chitinous ring with two projections).  
 
  
== Life-Cycle ==
 
Each worm has male and female segments, which reproduce via '''hermaphroditism'''.  The male segment fertilises the female segment. The reproductive organs then deteriorate, leaving only a uterus full of eggs.  This then detaches from the rest of the worm and migrates to the large intestine, where it ruptures releasing the eggs.
 
  
The eggs released are infective to '''oribatid mites''', which act as the intermediate host. These mites live in the ground, feeding on plant debris. These are ubiquitous, but most numerous on permanent pasture in the summer months.  
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=== Recognition ===
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*Superficially, ''A. perfoliata'' looks more like a trematode than a tapeworm, but closer inspection reveals that the body compromises many segments that are wide, but very short.
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*It typically grows to approximately 5cm, but can be longer.  
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*The gravid segment contains characteristic eggs with a ‘rounded triangular’ shape.
 +
*The oncosphere is contained in the ‘pyriform apparatus’ (a chitinous ring with two projections).
 +
*The eggs do not float well in the flotation fluids used in routine faecal examination and may be overlooked. Special techniques are required for this purpose, but none are reliable. An ELISA has therefore been developed to demonstrate specific antibodies in blood.
  
The mites ingest the egg.  [[Cyclophyllidea Life-Cycle|'''Cysticercoid''']] larvae hatch, and live within the mite for its entire life.  These cysticercoids become infective around two weeks after hatching.
 
  
The horse, which acts as the definitive host , ingests the mites in spring, when grazing the pasture. 
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=== Life-Cycle ===
 
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The intermediate hosts of ''A. perfoliata'' are free-living pasture mites. These are ubiquitous, but most numerous on permanent pasture in the summer months. The metacestode form is the cysticercoid. Horses become infected by ingesting the mites while grazing.
They attach to the mucosa, and transform into adults in around 6- 10 weeks.  The adults live in the '''ileum''', at the '''ileocaecocolic valve''', and within the '''caecum'''. The adults are capable of shedding large numbers of eggs.
 
 
 
The adults live for 4-6 months, and disease is most commonly seen between October and November.
 
 
 
The prepatent period is 6-10 weeks.
 
 
 
{{Learning
 
|flashcards = [[Cestodes_Flascards|Cestodes Flashcards]]
 
|literature search = [http://www.cabdirect.org/search.html?rowId=1&options1=AND&q1=Anoplocephala&occuring1=title&rowId=2&options2=AND&q2=&occuring2=freetext&rowId=3&options3=AND&q3=&occuring3=freetext&x=64&y=11&publishedstart=yyyy&publishedend=yyyy&calendarInput=yyyy-mm-dd&la=any&it=any&show=all ''Anoplocephala'' publications]
 
|Vetstream = [https://www.vetstream.com/canis/search?s=tapeworm Cestoda]
 
}}
 
 
 
 
 
{{review}}
 
 
 
{{OpenPages}}
 
  
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''A. perfoliata'' is found mainly in the caecum, clustered around the ileo-caecal junction, where it causes superficial ulceration and mild inflammation. Generally, it is of little clinical significance, but epidemiological evidence suggests that heavy infections (greater than 20 tapeworms) are a significant risk factor in some forms of colic.
 
[[Category:Anoplocephalidae]]
 
[[Category:Anoplocephalidae]]
 
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[[Category:To_Do_-_Max]]
[[Category:Expert_Review]]
 
[[Category:Horse Parasites]]
 

Revision as of 14:39, 13 July 2010



Anoplocephala Species

Anoplocephala - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona

Several species of Anoplocephala occur in equidae, but A. perfoliata is the only common species in the UK.


Recognition

  • Superficially, A. perfoliata looks more like a trematode than a tapeworm, but closer inspection reveals that the body compromises many segments that are wide, but very short.
  • It typically grows to approximately 5cm, but can be longer.
  • The gravid segment contains characteristic eggs with a ‘rounded triangular’ shape.
  • The oncosphere is contained in the ‘pyriform apparatus’ (a chitinous ring with two projections).
  • The eggs do not float well in the flotation fluids used in routine faecal examination and may be overlooked. Special techniques are required for this purpose, but none are reliable. An ELISA has therefore been developed to demonstrate specific antibodies in blood.


Life-Cycle

The intermediate hosts of A. perfoliata are free-living pasture mites. These are ubiquitous, but most numerous on permanent pasture in the summer months. The metacestode form is the cysticercoid. Horses become infected by ingesting the mites while grazing.

A. perfoliata is found mainly in the caecum, clustered around the ileo-caecal junction, where it causes superficial ulceration and mild inflammation. Generally, it is of little clinical significance, but epidemiological evidence suggests that heavy infections (greater than 20 tapeworms) are a significant risk factor in some forms of colic.