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Dicrocoelium dendriticum (view source)

Revision as of 10:49, 16 July 2010

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==Life Cycle==
 
==Life Cycle==
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After mating, the eggs are excreted in the faeces.  The first intermediate host, the snail, eats the faeces and ingests the infective larvae.  The larvae then grow and develop in the host.  The larvae are then extruded in the slime.  This phase requires around 3 months for completion.
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The slime balls are then ingested by the ant, along with the developing larvae, known as cercariae.  In the ant they mature into metacercariae.  The presence of metacercariae in the nerve ganglia of the ants makes them revert to a primitive behaviour pattern, whereby they cling onto herbage overnight instead of retreating to the nest enhancing the likelihood of being eaten by grazing animals
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Infection of the definitve host is via ingestion of ants, mainly on the pasture.  The metacercariae moult into immature flukes and migrate directly up the bile duct into the liver.
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*This is a small fluke (<1.5cm) found in the bile ducts of ruminants and some other herbivores
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*The flukes migrate directly up the common bile duct to reach the bile ducts within the liver
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**They are therefore much less pathogenic than ''Fasciola'' (which burrow through the liver parenchyma)
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*''Dicrocoelium'' is rare in Britain, occurring mainly in the Hebrides, but is common in Europe
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**These contain a miracidium
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**If ingested by a land snail, the flukes develop, forming cercariae
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**These are excreted by the snails in slime-balls, which are collected and eaten by wood-ants
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**Metacercariae form inside the ants
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**The final host is infected when ants are eaten at grazing
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**The presence of metacercariae in the nerve ganglia of the ants makes them revert to a primitive behaviour pattern, whereby they cling onto herbage overnight instead of retreating to the nest enhancing the likelihood of being eaten by grazing animals
   
[[Category:Trematodes]]
 
[[Category:Trematodes]]
    
[[Category:To_Do_-_Max]]
 
[[Category:To_Do_-_Max]]
Cmcory
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