Schistosoma haematobium - MegaMicro

Schistosoma haematobium

 

 

Schistosoma haematobium

 

1.      Organism:  

 

a.       Trematode (Helminth) found in Africa and the Middle East

 

b.      Pathobiology:

 

Lifecycle: Freshwater is contaminated with eggs in urine and fecesà eggs hatch and release miracidiaàmiracidia penetrate snail tissueàsporocysts in snail go through an amplification processàcercariae are released by the snail into H2O and they are free swimmingà cercariae penetrate human skinà become schistomulae in circulationà migrate through portal venous system where they mature and mate à then they migrate to the veins surrounding the bladder to lay their eggsà these eggs can then enter the lumen of the bladder where they can be excreted into the urine and continue the life-cycle

 

c.       Epidemiology:

 

                                                             i.      Intermediate host: snails (fresh water)

 

                                                           ii.      Definitive host: human

 

                                                         iii.      Freshwater in Africa

 

d.      Laboratory diagnosis:

 

-eggs detected in the urine (have a terminal spike)

 

-serology is the most sensitive

 

-eosinophilia

 

-blood in the urine for screening test

 

e.       Disease manifestations:

 

                                                             i.      -Swimmers itch-due to larval penetration of the skin

 

                                                           ii.      -Katayama fever- hepatomegaly, eosinophilia (acute phase)

 

                                                         iii.      -Haematuria, dysuria, proteinuria, chronic infection (Salmonella), renal failure, and bladder cancer risk

 

f.       Therapy:

 

-praziquantel

 

g.      Prevention and control:

 

-sanitation

 

-safe water

 

-snail control (where possible)

 

-avoid fresh water exposure in endemic areas

 

 

 

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