raed z. ahmed, medical parasitology lab.,2012. fasciola hepatica fasciola hepatica lives in the...
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Fasciola hepaticaFasciola 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 MiracidiumFasciola hepatica Miracidium
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Fasciola hepatica cercariaeFasciola hepatica cercariae
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Fasciola hepatica rediae larvaeFasciola hepatica rediae larvae
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Schistosoma sppSchistosoma 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
SnailSnail
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Oncomelania spp.Biomphalaria spp.
Bulinus spp.
Schistosoma spp. Schistosoma spp. EggsEggs
Raed Z. Ahmed, Medical Parasitology Lab.,2012
S. japonicumS. haematobiumS. mansoni
Lateral spine
Terminal spine Rounded spine
Schistosoma cercariaSchistosoma cercaria
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Bifid tail
Oval head
Schistosoma Schistosoma adult maleadult male
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Adult male short, thick and have gyanchophoric canal
Schistosoma Schistosoma adult femaleadult female
Raed Z. Ahmed, Medical Parasitology Lab.,2012
Adult female longer and thinner than adult male.