Primaquine-induced changes in morphology of exoerythrocytic stages of malaria.

Exposure to primaquine for 48 hours caused lesions in the exoerythrocytic stages of Plasmodium fallax grown in cultivated cells derived from embryonic turkey brain. The lesions appeared in the form of cytoplasmic vacuoles when viewed under the light microscope. The electron microscope revealed these vacuoles as swollen mitochondria readily identifiable by their typical protozoan cristae. Mitochondria of the host cell were unaffected.