Genealogy of A. phagocytophilum haplotypes. Only 228 isolates of out of 548, representing all 97 haplotypes are shown. Of each haplotype, only one isolate per host from each country is used. An open circle is a haplotype. It is colored by the isolation origin (host species) and drawn in proportion to the sample size. A small blue dot is a missing haplotype. A blue edge is a mutation. The haplotype genealogies were made using Haploviewer software . Roman numerals label the four ecotypes, which were inferred from a phylogenetic tree (Additional file 2: Figure S1).