Schistosoma haematobium

In some parts of southern Iraq the onset of macroscopic haematuria in pubescent males is regarded as almost a normal development - akin to the onset of menstruation in females - owing to the wide prevalence of infection with Schistosoma haematobium. In Nigeria, the most common causes of acute renal failure are typhoid and snake-bite, usually envenomation from a puff adder bite.

In sub-Saharan Africa, malarial infection remains an extremely common cause of glomerulonephritis. In black Africans living in urban (as distinct from rural) areas, hypertension is exceptionally common, being characterized by relatively low levels of renin and normal levels of aldosterone in blood. Such hypertension has a particular predilection for inducing kidney damage and it is likely - although data are scant - that end-stage renal failure due to hypertensive nephropathy in urban blacks is extremely common.

Certainly in the UK and USA, end-stage renal failure is reached at about four times the rate in blacks compared with whites and hypertension is a major cause of this. It appears that less efficient renal excretion of sodium in blacks versus whites explains some of these observations.

In rural sub-Saharan Africa, dietary salt intake is in general very low and in a hot country where sodium intake is low, reduced renal capacity to excrete sodium might well have been an evolutionary advantage. Exposure to a higher dietary salt intake in cities may well account, in part at least, for the high prevalence of hypertension in urban blacks.

The vast majority of black individuals reaching end-stage renal failure in sub-Saharan Africa die untreated since facilities for dialysis and transplantation are, by comparison with developed countries, minimal.