Monday, February 25, 2013

Case of the Week 247

A businessman recently returned from India with recurring fevers and malaise.  The following were seen on peripheral blood films.  Identification? (CLICK ON IMAGES TO ENLARGE)

Giemsa stain, 1000x original magnification


Pearlie said...

I think this is P. vivax? Infected RBCs are enlarged, with Schuffner's dots and ameboid-shaped RBCs.

Malassezia said...

P. vivax. What a beautiful doubly infected cell!

Anonymous said...

Infected RBCs are larger than non infected RBCs indicating a predilection for younger red cells: This eliminates P. malariae, P. falciparum as well as P. knowlesii. There is no fimbriation among the infected RBCs, plus the geographical area visited is not a hot bed for P. ovale.
The identification based on morphology is consistent with P. vivax.

Florida fan

Anonymous said...

Vivax - The trophozoites look vivacious!

ABG said...

This is unmistakably P. falciparum
1.Ring forms
2. Multiple or super infection in one RBC

Anonymous said...

Plasmodium vivax

Anonymous said...

no way it is falciparum !

Anonymous said...

I am sticking with the crowd. Vivax. Stippling, ameoboid rings, larger than surrounding RBCs.


Anonymous said...

This is vivax. Beautifully stained! Thanks for the images.

Philip Coyne

Anonymous said...

P.vivax based on the size of infected RBCs. I didn't know that one red cell can be infected by multiple rings..

-from the Philippines

Anonymous said...

P.vivax .cant explain 2 rings in 1 rbc:-)

Charo said...

I think is Babesia. Because:

1. It has extra-cellular forms.
2. Size variability of ring-forms.
3. There is something like a "tennis racket-shaped" rings in the second photo. Babesia spp. tend to produce atypical forms, with multiple chromatin dots, 'double' rings, and chromatin 'tails'
4. There is not malarial pigment.
5. There are erythrocytes with several rings, but these are a bit thick to be P. falciparum.
“Alea jacta est” Now we have to wait

Charo again said...

it can also be a mixed infection of vivax-falciparum. Anyway, it is an intriguing case.

Anonymous said...

P. vivax.

From these slides, it is not a falciparum-vivax coinfection. Otherwise, we would see both enlarged RBCs with rings (vivax) and normal-sized RBCs with rings (falciparum).

Doubly-infected cells are quite uncommon outside of in vitro culture, so that last image is particularly cool. I would guess that multiply-infected cells are more common in P. vivax infections since there are not as many reticulocytes in circulation compared to erythrocytes.