It's time for our monthly case from Idzi Potters and the Institute of Tropical Medicine, Antwerp!
The following structure was seen in a lugol-stained wet preparation of concentrated feces.
The corresponding iron hematoxylin stained fecal smear showed the following:
7 comments:
E.histolytica trophs
E. histolytica
Bw from Vt
While the organisms resemble E histolytica, they are smaller. This is characteristic of E hartmanni
Entamoeba hartmanni.
Nice pseudopods, thin peripheral chromatin ring, small central chromatin dot. The overall size estimates about eight to ten microns compared to the bar, this falls into the size range of E. hartmani or formerly called E. histolytica small race. The margin for distinction is twelve microns or greater to match with E. histolytica/dispar.
Florida Fan
Beautiful pictures!
I think we are looking at Entamoeba hartmanni cyst and trophozoite.
Two other protists we must consider in our differential diagnosis are Entamoeba histolytica/dispar/moshkovskii/bangladeshi and Endolimax nana.
As stated by Florida fan, cyst dimension is the main characteristic that separates E. histolytica/dispar/moshkovskii/bangladeshi from E. hartmanni. Trophozoites' dimension is not as reliable, since E. hartmanni can become bigger in case of Sphaerita infection.
The nuclear characteristics allow us to discriminate between E. hartmanni and E. nana, especially the karyosome aspect in the stained trophozoite. It is clearly dot-like, whereas limax-like nuclei have a much bigger karyosome. Moreover the cyst appears somewhat refractile, and this helps us to rule out Endolimax nana.
Luca Fanasca, MD
Would this be an example of an enteric bacteria? I wonder what are the means of exposure and the mechanism of its virulence!
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