SummaryThere is no absolutely clear point at which early trophozoites of P.vivax become late trophozoites as it is simply a process of continuous development. However, the transition to an amoeboid parasite form where the original ring structure can no longer be seen will certainly place the parasites at this stage.
Very early double dot form Very early red cell changes with fine dots visible
Early ring form Dots are more visible and the red cell begins to show distortion.
Early ring form The ring has thickened with established dots and altered red cell size
Intermediate ring Amoeboid parasite within an enlarged distorted red cell with marked dots