Thus, anaemia cannot be due to decreased RBC production, but is more likely due to increased RBC destruction, either by parasite invasion and a bystander effect, and to suppression of the erythropoietin-dependent up-regulation of erythropoiesis in response to anaemia, despite elevated levels of erythropoietin in this macaque cohort between Days 20 and 30 [36]. Here, EPO is linked to anemia (phenotype).