elephantiasis is a disease that is characterized by the thickening of the skin and underlying tissues, especially in the legs and male genitals
it is caused by either:
filariasis in tropical regions and Africa - especially Kenya where 6% of the population are affected in endemic areas
podoconiosis which is thought to be caused by persistent contact with irritant soils, in particular, red clays rich in alkali metals such as sodium and potassium and associated with volcanic activity