Figure 1: A ring form, an early ameboid trophozoite with co-existing Schuffner stippling and a mature schizont can be seen in one field. Note that the red blood cells hosting the trophozoite and the schizont are larger than the surrounding non-parasitized red blood cells. (Wright stain, X1000)


 

A presumptive diagnosis of malaria was made. The patient was begun on quinine sulfate and doxycycline. Three hours later, his platelet count was 6,000/ul. He received ten units of random donor platelets, but his platelet count rose to only 24,000/ul. Eighteen hours later he experienced spontaneous epistaxis and received ten units of random donor platelets. His platelet count rose to 64,000/ul and the bleeding stopped. His platelet count remained in the 50-60,000/ul range for three days and then became normal.

Peripheral blood smear examination revealed that approximately two percent of red blood cells harbored parasites. The parasites ranged from ring forms to more mature trophozoites with Schuffner stippling (Figure 2).

 

Figure 2: Maturing trophozoite with Schuffner stippling. (Wright stain, X1000)


 

Many mature schizonts containing malaria pigment and gametocytes were also present (Figures 3 and 4). Parasitized red blood cells appeared larger than non-parasitized cells. Occasional red blood cells were noted to contain more than one ring form. The schizonts consistently possessed in excess of twelve nuclei. The white blood cells appeared normal qualitatively and quantitatively; no malaria pigment was seen in neutrophils.

 

Figure 3: A mature schizont possessing in excess of 16 merozoites. (Wright stain, X1000)


 

 

Figure 4: A ring form and a gametocyte are present in this field. (Wright stain, X 1000)


 

The findings supported a diagnosis of malaria due to P. vivax.