Sunday, December 13, 2009

Answer to Case 97

Answer: Plasmodium ovale (trophozoites)
Congratulations to everyone who wrote in with the answer - you all recognized the classic appearance of P. ovale in a thin smear of peripheral blood. Like P. vivax, P. ovale has prominent stippling (a.k.a. Schuffner's dots) and enlargement of the infected red blood cells, but the trophozoite forms are more compact than P. vivax, and many of the infected red blood cells (approximately 1/3) are elongated or oval in shape (hence the name ovale). In addition, one edge of the infected cells is often ragged or fimbriated. The characteristic features are outlined below:

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