An investigation of the protective effect of alpha+‐thalassaemia against severe P lasmodium falciparum amongst children in K umasi, G hana

Summary Introduction Several factors influence the severity of P lasmodium falciparum ; here, we investigate the impact of alpha+‐thalassaemia genotype on P . falciparum parasitemia and prevalence of severe anaemia amongst microcytic children from K umasi, G hana. Methods Seven hundred and thirty‐two children (≤10 years) with P . falciparum were categorised into normocytic and microcytic (mean cell volume ≤76 fL). Microcytic individuals were genotyped for the −α 3.7 deletional thalassaemia mutation and parasite densities determined. Results Amongst microcytic patients both parasite densities and prevalence of severe malaria parasitemia (≥100 000/μL) were significantly lower ( P  < 0.001) in the presence of an alpha+‐thalassaemia genotype compared with non‐alpha+‐thalassaemia genotype. There was no evidence that alpha+‐thalassaemia protected against severe anaemia. The protection conferred by alpha‐thalassaemia genotype against severe P . falciparum parasitemia did not change with increasing age. Conclusion The severity of P . falciparum parasitemia was significantly lower in both the homozygous and heterozygous alpha+‐thalassaemia groups compared with microcytic individuals with non‐alpha+‐thalassaemia genotype. The protective effect, from severe malaria, of the alpha+‐thalassaemia allele does not alter with age.