Raed Z. Ahmed, Medical Parasitology Lab.,2012

Fasciola hepatica Fasciola hepatica lives in the liver of man. Fasciola spp. have many stages: Oval eggs have miracidium, cercaria, metcercaria, larvae and adult stage. Intermediate host: Snail. Definitive host: Sheep. Infective stage (human): Metacercaria. Human infected by ingestion metacercaria from infected sheep. Diagnosis: –Stool analysis to find Fasciola egg. Raed Z. Ahmed, Medical Parasitology Lab.,2012

Fasciola hepatica Egg Raed Z. Ahmed, Medical Parasitology Lab.,2012

Fasciola hepatica Miracidium Raed Z. Ahmed, Medical Parasitology Lab.,2012

Fasciola hepatica cercariae Raed Z. Ahmed, Medical Parasitology Lab.,2012

Fasciola hepatica rediae larvae Raed Z. Ahmed, Medical Parasitology Lab.,2012

Fasciola hepatica Adult Raed Z. Ahmed, Medical Parasitology Lab.,2012

Schistosoma spp. Also known as bilharzia, cause schistosomiasis or bilhariziasis. Schistosoma spp. have 4 stages: –Eggs, miracidia, cercaria, and adult stage. Eggs are passed through urine or feces to fresh water, where larvae stage can infect a new host by penetrating the skin. Schistosoma eggs are non- operculated but spined and have miracidum. Eggs hatch and release miracidia in water. Miracidia move in water looking for a special snail, and penetrate a snail tissue and developed to sporocyst. Cercaria releasaed by snail into water and free swimming, cercaria has a bifid tail and penetrate intact skin Cercaria lose tail during penetration and become schitosomulae, that circulate in the blood and migrate to portal blood of liver and mature into adult. Raed Z. Ahmed, Medical Parasitology Lab.,2012

Schistosoma spp. Schistosoma spp. (cont….) There are three medically important species: –Schistosoma mansoni, lives in the mesenteric venules of large intestine, and cause intestinal bilharziasis. –Schistosoma japonicum, lives in the mesenteric venules of small intestine. –Schistosoma haematobium, lives in the venous plexus of the urinary bladder and cause schistosomal hematuria or urinary bilhariziasis. S. mansoni and S. japonicum are produce their eggs in stool, but S. haematobium produce eggs in urine. Raed Z. Ahmed, Medical Parasitology Lab.,2012

Schistosoma spp. Schistosoma spp. (cont….) Intermediate host: snail. Definitive host: human. Cercaria is the infective stage but eggs are the diagnostic stage. Diagnosis:  Depends on finding the characteristic ova in feces or urine.  Three species can be distinguished by the appearance of their eggs under microscope: S. mansoni eggs have prominent lateral spine. S. japonicum eggs have a very small round lateral spine. S. Haematobium eggs have a terminal spine. Raed Z. Ahmed, Medical Parasitology Lab.,2012

Snail for Schistosoma spp. Raed Z. Ahmed, Medical Parasitology Lab.,2012

Snail Oncomelania spp.Biomphalaria spp. Bulinus spp.

Schistosoma spp. Eggs Raed Z. Ahmed, Medical Parasitology Lab.,2012 S. japonicumS. haematobium S. mansoni Lateral spine Terminal spineRounded spine

Schistosoma miracidium Raed Z. Ahmed, Medical Parasitology Lab.,2012

Schistosoma cercaria Raed Z. Ahmed, Medical Parasitology Lab.,2012 Bifid tail Oval head

Schistosoma adult male Raed Z. Ahmed, Medical Parasitology Lab.,2012 Adult male short, thick and have gyanchophoric canal

Schistosoma adult female Raed Z. Ahmed, Medical Parasitology Lab.,2012 Adult female longer and thinner than adult male.