Babesia microti Genome sequencing and assembly

Human babesiosis due to Babesia microti is an emerging zoonosis of increasing importance due to rising prevalence and expanding geographic range. To investigate the origin and genetic diversity of this parasite, we sequenced the complete genomes of 38 B. microti samples from around the world, including deep coverage of clinical infections at endemic sites in the continental United States. We show that B. microti is an ancient species complex with extensive worldwide diversity, but that samples from the US possess limited genetic diversity while segregating into two major lineages residing in the Northeast and Midwest. Analysis of a case of azithromycin failure implicates bmRPL4 as the probable target of azithromycin in B. microti. Our results shed light on the origin, diversity, and evolution of B. microti, and create the foundation for further research on this emerging pathogen.