P. All stages of P. vivax accumulated in the spleen at magnitudes unexplainable by replication occurring in the circulation alone, with the proportion of each stage in the spleen consistent with the duration in their lifecycle. What do these findings mean? Taking advantage of the large physiological splenic reservoir of immature reticulocytes, the majority of the P. vivax lifecycle can take place in the spleen in chronic malaria. Chronic vivax malaria should be considered predominantly an infection of the reticulocyte-rich spleen, with secondary involvement of the intravascular compartment. The spleen is not solely a compartment for parasite destruction and clearance.