Answer to Case 62
This was a case of malaria caused by Plasmodium ovale.  Diagnostic features observed were

• Some infected red blood cells exhibited stippling/Schüffner’s dots (Figures A, B, and C).
• Some trophozoites were slightly ameboid (Figures C and D) while others were compact; most showed a large nucleus (chromatin dot).  Most parasites were in slightly enlarged and/or oval red blood cells with some appearing fimbriated (Figures A and D).
• The gametocytes shown (Figures E and F) in this case were greatly distorted, almost resembling those of P. falciparum.  Closer scrutiny, however, revealed that the pigment was too dispersed and that the gametocyte was, in fact, just abnormally shaped.  A few gametocytes were seen on the slide, several of which were deformed.
• The schizonts (Figures G, H, and I) contained 9 to 14 nuclei and were found in slightly enlarged red blood cells.  Some schizonts had centrally located or clumped coarse pigment.  This feature, sometimes seen in P. ovale infections, should not be confused with P. malariae schizonts, which typically have the rosette configuration, but fewer nuclei.

PCR analysis was performed and confirmed the species of Plasmodium to be P. ovale.  For more information on malaria, click here.