Morphologic effects of artemether on Plasmodium falciparum in Aotus trivirgatus

The effects of artemether on the morphology of Plasmodium falciparum were studied in an owl monkey (Aotus trivirgatus) when parasitemia reached 33% and the animal became severely ill. The earliest and the most distinctive ultrastructural changes following the administration of artemether were marked swelling of the mitochondria in the parasites, followed by the appearance of electron-dense chromatin materials in the nuclei and clumping of ribosomes. The initial change was observed within 2 hr of administration of the drug. These findings correlate well with the rapid and effective action of artemether, which has been demonstrated in human clinical trials.