Maintenance of High Sickling Rate in an African Community

A Study of the Survival Rate of Cases of Sickle-cell Anaemia

“…This figure of 14% survival rate lies between the estimates made by Allison (1956), on the one hand, and by Lehmann and Raper (1956) and the workers in the Belgian Congo on the other. The difference might be explained on the basis of the smaller samples of Allison and of Lehmann and Raper; and the Congo workers, relying on clinical diagnosis, might have missed just those mild cases which might be expected to survive to adult life.…”

“…He later suggested that the survival rate in Africa was more likely to be in the region of 200% on the basis of figures collected from the Musoma tribe of Tanganyika (Allison, 1956). In a survey of the Baamba tribe in Uganda, Lehmann and Raper (1956) found no case showing the electrophoretic pattern of sickle-cell anaemia in a random sample of 478 adults. They conclude " that the survival of sickle-cell homozygotes plays no significant part in the maintenance of the high sickling rate in the Baamba."…”

“…Both this latter disease and the anaemia often resulting from the double inheritance of two abnormal haemoglobins may produce a clinical picture closely similar to sickle-cell anaemia. In East Africa, however, other abnormal haemoglobins have not been found among the African tribes (Jacob, 1955;Roberts and Lehmann, 1955) and thalassaemia has never been detected. The same situation appears to obtain in the Belgian Congo.…”

Burkitt's Lymphoma: A Time-space Cluster of Cases in Bwanba County of Uganda

“…Malaria is hyperendemic (McCrae, 1968) and 39"' of the people have sickle-cell trait (Lehmann and Raper, 1956 The diagnosis of Burkitt's lymphoma in all seven patients was confirmed histologically. The series excludes an additional patient (clinical onset in September 1968) from the same area of Bwamba, whose clinical symptoms and response to therapy were characteristic of Burkitt's lymphoma but whose histological diagnosis was that of histiocytic lymphoma.…”

Malaria continues to select for sickle cell trait in Central Africa

“…It is due to a mutation of the gene coding for the β-globin, called the hemoglobin (Hb)S mutated allele, whereas the wild type is called the HbA allele (5). In the homozygous condition (hereafter denoted as HbSS), this mutation causes a severe disease, sickle cell anemia, which was almost always lethal before the advent of modern medicine, and still is where modern medical care is not available (6,7). In the heterozygous condition (HbAS), called sickle cell trait (SCT), the mutation results in a much milder condition to the point that carriers may go unnoticed, although it has been associated with a variety of conditions or diseases like hematuria, splenic infarction, and exerciserelated sudden death (8).…”