Clinical and Pathological Outcomes of Experimental Plasmodium fragile Infection in a Rhesus Macaque

The anatomical and immunological similarities between humans and nonhuman primates (NHPs) make NHPs a viable model for examining Plasmodium spp. infection outcomes. Plasmodium fragile was previously used to model human severe malaria in NHPs using rhesus macaques (RMs), but a thorough investigation of the clinical and pathological effects of RM P. fragile infection has not yet been conducted. In this study, we observed that experimental infection of a male RM with P. fragile-infected erythrocytes resulted in clinical signs of malaria, including anemia; changes in red and white blood cell distribution; changes in red blood cell morphology; and gross and histopathological alterations to vital organs, such as the liver, lungs, heart, and brain. Plasmodium fragile-infected red blood cells were also observed in the vasculature of major organs, including the spleen, liver, lung, and brain. These results suggest that experimental P. fragile infection of RMs is a translatable model of human malaria.