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Parasitology
Author: Nat Pernick, M.D., PathologyOutlines.com, Inc.
Revised: 24 June 2009
Definition
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● Fluke that causes colitis or bowel obstruction
● Also known as bilharzia, bilharziosis or snail fever
Epidemiology
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● Associated with underdeveloped countries and living near dam reservoirs (Lancet Infect Dis 2006;6:411)
● S. haematobium: Africa and Middle East; usually affects bladder; diagnosed with urine examination
● S. intercalatum: central West Africa; uncommon
●
S. japonicum: Southeast Asia and western Pacific countries; diagnose with stool
examination
● S. mansoni: South America, Caribbean, Africa and Middle East; diagnose with stool examination
● S. mekongi: Southeast Asia; uncommon
Case reports
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● 31 year old woman with associated endometriosis (Fertil Steril 2006;85:1060.e1)
● 78 year old man with rectal adenocarcinoma (Univ Pittsburgh Case #199)
Gross images
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Schistosoma granulomas
Micro description
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● Focal ulcers, eggs may be calcified, surrounded by fibrosis or granuloma
●
S. haematobium - eggs are 110-170 x 40-70 microns, oval with terminal
spine
● S. japonicum - eggs are
70-100 x 55-65 microns, oval/round (more rounded than other types), minute subterminal
or no spine
● S. mansoni - eggs are 110-175 by 45-70 microns with thin transparent shell and definite lateral spine
Micro images
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All subspecies
Schistosoma haematobium - oval eggs with terminal spine
Schistosoma haematobium Fluke
Schistosoma haematobium Eggs
Contributed by Drs. Kiran Alam, Anshu Jain, Veena Maheshwari, Farhan A. Siddiqui and Ershadul Haq, J.N. Medical College, India
Transitional epithelium of ureter Schistosome eggs in Schistosome eggs in
with Schistosoma haematobium submucosa muscle layer
eggs in submucosa and muscle
Schistosome eggs in muscle layer - note terminal spine
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Schistosoma japonicum - small eggs, more rounded, no / minute terminal spine
Schistosoma japonicum Eggs
fluke
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Schistosoma mansoni - lateral spine
Schistosoma mansoni fluke
Schistosoma mansoni eggs
Contributed by Dr. Jennifer Stumph, Spectrum Health, USA
37-year-old woman with S. mansoni eggs in colon biopsy
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Schistosoma images – type not identified
Within tissue
Contributed by Dr. Lisa Cerilli
Within colonic mucosa
Other images: granuloma surrounding egg
Virtual slides - Schistosomiasis
References
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● eMedicine #1, #2, Centers for Disease Control, Wikipedia, World Health Organization, Archives 2005;129:544 (S. mansoni)
End of Parasitology > Schistosomiasis
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