Sudan: the possible original focus of visceral leishmaniasis.

Fifty-two Leishmania strains, obtained from human patients and dogs in a visceral leishmaniasis focus in Sudan, were characterized by isoenzyme electrophoresis (15 enzymes). The phylogenetic analysis showed that the 7 Leishmania zymodemes obtained hold ancestral positions on the phylogenetic tree, supporting the hypothesis of an East African origin of visceral leishmaniasis.