Microbe Profile: Ehrlichia ruminantium - stealthy as it goes

Ehrlichia ruminantium is an obligate intracellular pathogenic bacterium that causes heartwater, a fatal disease of rumi-nants in tropical areas. Some human cases have also been reported. This globally important pathogen is primarily trans -mitted by ticks of the Amblyomma genus and threatens American mainland. E. ruminantium replicates within eukaryotic mammal or tick cell is a membrane- bound vacuole, where it undergoes a biphasic developmental growth cycle and differ-entiates from noninfectious replicative form into infectious elementary bodies. The ability of E. ruminantium to hijack host cellular processes and avoid innate immunity is a fundamental, but not yet fully understood, virulence trait of this stealth pathogen in the genomic era.