Maintenance of High Sickling Rate in an African Community

Abstract

The Baamba, an African tribe showing a high sickling rate (39%) has been examined to determine how this high rate can be maintained. Of the 623 subjects examined, 227 were sicklers. No genetic variants of normal adult haemoglobin other than haemoglobin S were found. Amongst 191 sickling subjects over the age of 5 no homozygotes were detected; and it is concluded that the survival of sickle-cell homozygotes plays no significant part in maintaining the sickling rate of this tribe at its high level. If selective death of non-sicklers from malaria was responsible for the maintenance of the 39% sickling rate in Bwamba, 10.6-24.2% of all normal homozygotes (or 6.9-15.7% of the whole child population) would have to die from malaria. Reasons are given for supposing that the actual death rate to be observed would approximate to the lower rather than the higher of the two limits, and that such a death rate from malaria is to be expected in Bwamba. © 1956, British Medical Journal Publishing Group. All rights reserved.