Monday, September 17, 2012

Case of the Week 224

A 15-month old U.S. child spent 3 weeks in Nigeria with her parents.  On return, the following were seen in stool and blood specimens.

Peripheral blood, Giemsa, 1000x original magnification:

Stool, Trichrome, 1000x original magnification

 Stool, Modified Acid fast stain, 1000x original magnification


Many thanks to MicrobeMan for donating this case!


Anonymous said...

The blood case: only ring forms found, ring diameter smaller than half of infected red cell, infected cells not enlarged. A few ring have two nuclei, one applique form found. Based on these findings, the organism is consistent in morphology with P. falciparum.

The second case: A ring of nuclei distributed on the edge of the cell (actually think of it as a clear spherical glass ball and some body just stick a few globs of play dough, if you rotate this ball, you will see different variations in morphology of the distribution of the play dough globs). The identification is therefore B. hominis.

The acid fast smear: Very nicely done Kinyoun stain (using Basic Fuchsin as the stain and mehtylene blue counterstain). It should be emphasized that Cyclospora oocysts may in the same smear stain red with basic fuchsin and also may not take this dye and therefore appear as ground glass appearance.
We found more consistent staining with hot safranin as advocated by Dr. Visvesvara and al. The key is to expose the oocysts to hot safranin (between 80C to 95C). As far as decolorization, the old HCl 3% in 95% ethanol gives a cleaner decolorization without overkill. The counter stain can be either methylene blue or malachite green. With this method, you can spot Cyclospora oocysts at 100x total magnification and definitely identify them at 400x nagnification, thus shortening your examination time.

Florida fan

Anonymous said...

I think the last picture could also be Cryptosporidium sp.
Although it is quite big for Crypto.
(normally 4-6 um).
I see sporozoïds in the cyste.
On the other 2 picture I agree with Florida fan except nowadays you can't speak of Blastocystis hominis anymore but rather Blastocystis sp.

Hans Naus

Zoka said...

P.falciparum and B.hominis.

Anonymous said...

Picture 3 I think is Crypto, not Cyclospora.

According to 10 µm scalebar, the stained object is just over 5 µm. Somewhat large for Crypto, but not too large.
Cyclospora oocysts are around 7-10 µm, so I think it is too smal for that. Howwever, the stain is rather diffuse - however, I know it can be variable for both

DC29 said...

I think the Florida fan left his eyeglasses at work when he looked at the picture. To me its much less than 8 microns so definitely not a cyclospora.the microscopic characteristics matches a cryptosporidium.

Anonymous said...

OK,OK,OK. Yes, on closer examination (I used a ruler in mm to measure the bar and the oocyst, it measured 6-7nm). Therefore I believe Hans Naus and DC29 are right.

Florida fan

megha said...

P. falciparum ring stage(with applique n head phone appearance), Blastocystis sp. nd cryptosporidium.
Thanku very much for trichrome stained blastocystis, nice pic. i hv recently seen lots of blastocystis in stool wet smear but only vacuolar forms.
Can u next put pics for diff forms of the organism...
Hooked on ur blog...