Monday, October 9, 2017

Answer to Case 463

Answer: Schistosoma haematobium ova

The large size (~120 micrometers long), presence of a terminal spine, and location in urine are characteristic of this species, and this identification fits well with the history of hematuria in this patient. The other Schistosoma egg that has a similar appearance is S. intercalatum; in contrast to S. haematobium, it is most commonly found in stool and is somewhat longer (140-170 micrometers). It also has a central bulge, and infection is limited to east central Africa. The patient in this current case is from Northern Africa, outside of the area where S. intercalatum is present.

The video allows you to see the motility of the miracidium inside of the egg, including the "flame cells" (protonephridium). It can be helpful clinically to verify that the eggs are alive, as this indicates an active infection (unless the patient has been recently treated).

 We had a similar case in my lab last year which you can find as Case of the Week 417.

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