Figure 3.

Schematic of the possible mechanisms for delay in detection of infection. If parasite growth is reduced by blood stage immunity (A), the delay between the PCR and microscopy detections will be shorter in individuals with high growth (i) compared to patients with low PMR (ii). If infection is delayed because liver-stage immunity blocks some infective bites (B), then the delay between the PCR and microscopy detection is the same in individuals with low immunity (i) and in individuals with stronger immunity (ii). Incline lines indicate schematic parasite growth curves. Horizontal lines indicate the PCR and microscopy detection thresholds. Abbreviations: PCR, polymerase chain reaction; PMR, mean parasite multiplication rate.