Changes

 

Also known as: '''''Dicrocoelium lanceolatum — Small lanceolate fluke

== ''Dicrocoelium dendriticum'' ==

[[Image:Dicrocoelium dendriticum.jpg|thumb|right|150px|''Dicrocoelium dendriticum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]

[[Image:Dicrocoelium dendriticum.jpg|thumb|right|150px|''Dicrocoelium dendriticum'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]

[[Image:Dicrocoelium dendriticum adult.jpg|thumb|right|150px|''Dicrocoelium dendriticum'' adult from horse faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]

[[Image:Dicrocoelium dendriticum adult.jpg|thumb|right|150px|''Dicrocoelium dendriticum'' adult from horse faeces - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]

*This is a small fluke (<1.5cm) found in the bile ducts of ruminants and some other herbivores

 

**They are therefore much less pathogenic than ''Fasciola'' (which burrow through the liver parenchyma)

'''Intermediate hosts''': Land snails, mainly ''Zebrina detrita'' within Europe. Brown ants of the genus ''Formica'' are also required for completion of the life cycle.

*''Dicrocoelium'' is rare in Britain, occurring mainly in the Hebrides, but is common in Europe

 

**Small dark-brown eggs are shed in faeces

'''Definitive hosts''': ''D. dendriticum'' is most commonly seen in sheep, cattle, deer, and goats, but is occasionally seen in horses and pigs.

 

**If ingested by a land snail, the flukes develop, forming cercariae

**These are excreted by the snails in slime-balls, which are collected and eaten by wood-ants

**Metacercariae form inside the ants

The eggs are small dark-brown and are shed in the faeces by the infected host.

**The final host is infected when ants are eaten at grazing

 

**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

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.

 

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.

 

 

 

 

 

 

 

[[Category:Trematodes]]

[[Category:Trematodes]]