Hyperparasitaemia in falciparum malaria is often explained by protection of late stage parasites from the filtering action of the spleen. Unlike P. falciparum infections, all asexual developmental stages are seen in the peripheral circulation of knowlesi-infected patients [10] . Hyperparasitaemia in knowlesi malaria may not be modulated by splenic clearance in a similar manner as suggested for other non-sequestering human infections.