Experimental Infection with Plasmodium Falciparum in Aotus Monkeys

I. Parasitologic, Hematologic, and Serum Biochemical Determinations

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  • Department of Medical Zoology, Walter Reed Army Institute of Research, Washington, D.C. 20012

Aotus monkeys infected with the Camp strain of Plasmodium falciparum were studied with emphasis on hematologic, parasitologic and serum biochemical changes occurring during the course of infection. For most monkeys the infection was lethal, with survival times ranging from 4 to 18 days depending on the size of the inoculum. Decreases in red blood cell parameters occurred as the infection progressed, but were not accompanied by a pronounced reticulocyte response. Leucocyte levels appeared to be depressed early in the infection, but rose to high levels in some animals that survived for relatively long periods. This rise was accounted for by an increase in mononuclear leucocytes. Platelet levels were reduced to extremely low levels in most monkeys and were sometimes accompanied by hemorrhagic phenomena. Both serum transaminase and urea nitrogen levels increased while glucose levels decreased. Usually a gradual decrease in total serum protein was accounted for by decreases of both albumin and gamma globulin. Aggregates of erythrocytes containing schizonts and large trophozoites were found throughout the vasculature and were especially prominent in impression smears of the heart and liver. Many aspects of P. falciparum infections in Aotus were similar to infections with this plasmodium in man.