A geogenic origin has been proposed in the aetiology of non-filarial
elephantiasis of the feet and legs, recently renamed podoconiosis. Soil
collected in an area of the Ethiopian Rift Valley, the borough of
Ocholo, known for its high prevalence of podoconiosis (5.06%), has been
submitted to mineral analysis. High values of sulphur (S), cerium (Ce),
lanthanum (La) and neodymium (Nd), typical for basaltic bedrocks, were
found. Of special interest were the values for zirconium (Zr) and
beryllium (Be), 618 +/- 87 ppm and 4.6 +/- 0.5 ppm respectively, twice
as high as those recorded for soils sampled in neighbouring areas where
the prevalence of podoconiosis is low. To be noted also, a high content
in vanadium, above 250 ppm, in half of the soil samples collected in
this region. Year-long exposure of unprotected feet to Zr and Be, known
for their ability to induce granuloma formation in the lymphoid tissue
of man, and present in a clay rich in colloidal silica particle, highly
abrasive to skin, is doubtlessly a factor involved in the development of
lymph node sclerosis leading to elephantiasis.