English: Approximate historical distribution of P. vivax latency phenotypes. Areas where tropical "frequent relapse phenotypes" are prevalent are shown in pink. Areas where both frequent relapse and long-latency phenotypes have been reported are shown in purple, and areas where long-latency phenotypes were prevalent are shown in grey. Although both South America and India are generally considered to harbour frequent relapse phenotypes predominantly, there is evidence that long-latency phenotypes are present in both areas (particularly across the North of India), and without genotyping it may be difficult or impossible to distinguish the two phenotypes within an endemic area (Figure 22).