Synchronization of Plasmodium yoelii nigeriensis and P. y. killicki infection in the mouse by means of Percoll-glucose gradient stage fractionation: determination of the duration of the schizogonic cycle

The youngest (rings and young trophozoites) erythrocytic stages of Plasmodium yoelii nigeriensis and P. yoelii killicki, two rodent malaria subspecies developing very asynchronously in the blood, were separated from the other stages using a discontinuous Percoll-glucose gradient. They were inoculated into mice and the subsequent infection remained synchronous for two generations. The duration of the asexual cycle was found to be 18 h.