DigeneanreproductivesystemTestes(typically)paired;vasdeferensleadstogonopore,oftenwithcirrus(intromittentorgan).SpermintroducedintogenitalporeofanotherDigenean.Insomespecies(egClonorchis,Fasciola,Notocotylus)Laurer’scanalactsasavagina.

Ovary(typicallysingle)leadsthroughoviducttoootypewhichalsoreceivesvitellineducts.Fertilizationandshellformationoccurhere.Uterusleadstogenitalpore.Eggsleavebygenitalpore.

Developmentinsnail

Cercariae:miracidiaenterssnailbypenetrationormorerarelybyingestion.Developmentproceedsthroughsomecombinationofsporocyst,daughtersporocyst,redia,daughterredia.Culminatesincercariaewhichleavesnailtoinfectnewhost.

Cercariaevaryinformdependingongroup

Cercariaedooneofthreethings:

• Penetratefinalhost(egSchistosomaspp.)

• Penetrateandencystasmetacercariainvegetation(egFasciola,Quinquiserialis)

• Penetrateandencystonsecondaryintermediatehost(e.g.Clonorchis,Echinostoma,Dicrocoelium,Paragonimus)

Schistosomamansoni

Schistosomalifecycle

Schistosomamansoniinvenousdrainageoflargeintestine.

S.Japonicuminvenousdrainageofsmallintestine.

S.Haematobiuminvenousdrainageofurinarybladder(eggspassedinurine).

Echinostoma

Fasciolahepatica

Notocotylusquinqueserialis=Quinqueserialisquinqueserialis

Dicrocoeliumdendriticum

Paragonimuswestermani

Clonorchissinensis