Bartonella bacilliformis: dangerous pathogen slowly emerging from deep background.

Bartonella bacilliformis was perhaps the most lethal bacterial human pathogen in the pre-antibiotic era, but infections were and are limited to a specific geographical area, largely in Peru, corresponding to the range of its sand fly vector. B. bacilliformis targets both red cells and endothelial cells. Recent phylogenetic realignments have revealed a close genetic relationship to other bacteria which cause human diseases, including bacterial angiomatosis, to the former Grahamella species which infect red cells in other mammals, and to plant pathogens and symbionts including Agrobacterium tumefaciens and Rhizobium meliloti. Features of B. bacilliformis that contribute to its pathogenesis are slowly coming into view, and are here reviewed.