Case #461 – February, 2018

A 12-year-old boy, with symptoms of fever and chills after returning from a one month trip to an undisclosed West African country, was taken to a clinic for evaluation. It was determined that he had not taken any prophylactic medication for malaria prior to the trip. Blood smears were ordered, stained with Giemsa, and examined at 1000x magnification with oil at a pathology laboratory. Images were captured from a stained thin smear were sent to the DPDx Team for identification. Figures A – I 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 Pennsylvania Department of Health.

Figure A

Figure B

Figure C

Figure D

Figure E

Figure F

Figure G

Figure H

Figure I

This was a case of malaria caused by Plasmodium ovale. Diagnostic morphologic features shown included:

infected red blood cells (RBCs) demonstrating Schüffner’s stippling (Figures G – I).
infected RBCs that demonstrated elongation and/or fimbriation (Figures A, and D – F).
infected RBCs that are slightly enlarged 1.2x – 1.5xThis case was a bit challenging in that it did not present with all of the typical features necessary for the easy identification of Plasmodium ovale. For instance, only ring forms and immature trophozoites were seen in the smear. This is unusual for this species. The case however, highlights the importance of using Giemsa stain for malaria diagnosis, as it allowed for the visualization of Schuffner’s stippling. The morphology result was confirmed by PCR.

More on Malaria: https://www.cdc.gov/dpdx/malaria/index.html

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

DPDx is an educational resource designed for health professionals and laboratory scientists. For an overview including prevention, control, and treatment visit www.cdc.gov/parasites/.