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Monthy Case Studies - 2002
Case #79 - March, 2002
A physician was admitted to a hospital in January 2002 with a 3-week history of fever. He was treated empirically for pneumonia. He reported no recent travel outside the U.S. He reported no history of blood transfusions or intravenous drug use, and no needle sticks or cuts while performing surgery or other procedures. Blood smears were made from blood collected 1 day after this treatment. They were stained with Wright's-Giemsa and examined by the hospital laboratory and CDC (Figures A through G). The images were captured from one of the blood smears. What is your diagnosis? Based on what criteria?
Figure A
Figure B
Figure C
Figure D
Figure E
Figure F
Figure G
Answer to Case #79
This was a case of malaria caused by Plasmodium falciparum. Based on morphology alone, the identification was equivocal and additional testing was needed to definitively identify the parasite and make a diagnosis. The presence of only ring-stage trophozoites and the lack of pigment could not rule-out Babesia sp.
Serology and PCR were performed to confirm the diagnosis. The following are the serology titers:
- B. microti -- <1:8
- P. falciparum -- 1:4096
- P vivax -- 1:256
- P. malariae -- 1:1024
- P.ovale -- 1:256
The PCR results were negative for B. microti and positive for P. falciparum. Figure H is an image of the agarose gel showing the PCR diagnostic test results for detection of Plasmodium spp.
Legend: MS marker = molecular size marker; + = positive control; - = negative control.
Figure H
More on: Malaria
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.
