Fig. 4.

Origin and dispersal of Leishmania. A predecessor of L. donovani group and L. major would have evolved from monoxenous parasites of insects in South America ≈46–36 Mya and moved to Asia via the Bering land bridge (yellow line). The ancestor of the L. donovani complex diverged from other Leishmania species ≈14–24 Mya (red line). This predecessor arrived in central Asia and ≈1 Mya diverged into European L. infantum, African L. donovani and Indian/Kenyan L. donovani. L. infantum was later introduced in South America by European settlers, whereas L. donovani, represented here by strain LG16, would have been transferred by immigrants/slaves from India to Kenya and/or vice versa. Time estimates based on our data are in gray; those in white are taken from published literature.