Falciparum malaria mortality in sub-Saharan Africa in the pretreatment era

Area of Science:

• Genetics
• Epidemiology
• Tropical Medicine

Background:

• Sickle-cell trait offers protection against malaria, a significant health burden in sub-Saharan Africa.
• Balancing selection maintains high frequencies of the sickle-cell allele (hemoglobin S) in malaria-endemic regions.

Purpose of the Study:

• To estimate the historical burden of malaria-attributable childhood mortality in sub-Saharan Africa.
• To understand the impact of sickle-cell trait on population genetics and disease mortality.

Main Methods:

• Utilized population genetic data on hemoglobin S allele frequencies.
• Employed epidemiological modeling to infer mortality rates based on allele frequencies and known protective effects.

Main Results:

• Hemoglobin S allele frequencies range from 15% to 20% in high Plasmodium falciparum transmission areas.
• Estimated childhood mortality attributable to malaria in the pre-treatment era was between 15% and 24%.

Conclusions:

• The prevalence of sickle-cell trait is a direct indicator of historical malaria's severe impact on child survival.
• Understanding this genetic-mortality relationship is crucial for public health strategies in malaria-endemic regions.