Case #478 - October, 2018

A 4-year-old boy returned from a summer vacation in Tanzania with his parents with symptoms of fever and chills. He was evaluated at a clinic in St. Louis, Missouri where blood smears were ordered, stained with Giemsa and examined at 1000x magnification with oil. Images captured from the stained thin smear were sent to the DPDx Team for identification. Figures AF show what was observed in some of the images submitted. What is your diagnosis? Based on what criteria?

This case and images were kindly provided by the Missouri State Public Health Laboratory.


parasitic image

Figure A

parasitic image

Figure B

parasitic image

Figure C

parasitic image

Figure D

parasitic image

Figure E

parasitic image

Figure F

This was a case of malaria caused by Plasmodium malariae.  Morphologic features shown include:

  • Characteristic band form trophozoite with coarse pigment. (Figure F).
  • Infected red blood cells (RBCs), normal to 0.75x (Figures AF).
  • Ring stage parasites with delicate cytoplasm and prominent chromatin dot (Figure B).
  • Mature schizonts with 8-12 merozoites and coarse, dark brown pigment (Figures C and E).
  • Gametocytes in normal to 0.75x RBC;  both shown appear to be macrogametocytes based on presentation with compact, eccentric chromatin (Figures A and D).

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Images presented in the monthly case studies are from specimens submitted for diagnosis or archiving. On rare occasions, clinical histories given may be partly fictitious.

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Page last reviewed: December 20, 2018