Genetic characterization of flea-derived Bartonella species from native animals in Australia suggests host-parasite co-evolution

► We reported the association of Bartonella spp. and Australian fauna. ► The close association between marsupials, their fleas and Bartonella spp. is demonstrated. ► This finding suggests adaptation by Bartonella species to a specific ecological niche. ► The Bartonella spp. in the marsupial cluster appear to have evolved separately in Australian fauna.