Plasmodium falciparum Infection: Influence on Hemoglobin Levels in α-Thalassemia and Microcytosis

Plasmodium falciparum malaria, a-thalassemia, and anemia are frequent in African children. In 494 nonhospitalized Nigerian children, P. falciparum infection rates, a-globin genotypes, and hematologic parameters were determined. P. falciparum infection was observed in 78% of the children. The gene frequency of a-thalassemia was 0.28. Infection rates and parasitemia were similar for the 3 a-globin genotypes. In contrast to nonthalassemic and heterozygous persons, infection in children with homozygous a-thalassemia did not influence hemoglobin values. Because microcytosis and anemia are common features of a-thalassemia, their significance in P. falciparum infection was examined. Microcytosis was significantly associated with protection from hemoglobin decrease due to P. falciparum. Moreover, the rate of infection was lower in microcytic than in normocytic anemia.