Blood and bone marrow changes in malaria

A variety of abnormalities in the number, morphology and function of blood and bone marrow cells may be found in Plasmodium falciparum and P. vivax ma laria, in a non-immune individual, the nature of such abnormalities depends on the time after infection. in others it is determined by the pattern and intensity of malaria transmission in the area and the extent of host immun ity. Severe anaemia may occur in children with chronic falciparum malaria a nd low parasitaemia as well as in patients with complicated acute falciparu m malaria with high parasitaemia. However, the mechanisms underlying the an aemia in these two situations appear to be different. The possible roles of parasite products, T-cell-derived cytokines produced in response to the in fection, macrophage activation and hyperplasia, macrophage-derived factors such as tumour necrosis factor-a, and macrophage dysfunction in the pathoge nesis of the haematological abnormalities are discussed.