Potential similarity of relapse patterns with the long-latency and frequent relapse P. vivax phenotypes. The different colours and symbols represent different genotypes in two hypothetical infections. The upper panel shows the relapse pattern where the frequent relapse phenotypes are prevalent. The patient has hypnozoites from three preceding inoculations present at the time of illness from the newly acquired (red) infection. These are sequentially activated as proposed in Figure 21. Three relapses occur with similar periodicities, and a later randomly activated relapse occurs 8 months later. In the lower panel the long-latency phenotypes are present. Activation occurs as above and the long-latency relapse emerges nine months later. The initial relapse patterns associated with the two different phenotypes are identical. This illustrates the difficulty in excluding the presence of long-latency phenotypes in malaria endemic areas.