General Information: Rickettsia massiliae MTU5 was isolated from the tick Rhipicephalus turanicus collected from horses in Le Sambuc, Bouches-du Rhone, France. Members of this genus, like other Rickettsial organisms such as Neorickettsia and Anaplasma, are obligate intracellular pathogens. In both groups, the bacteria are transmitted via an insect, usually a tick, to a host organism where they target endothelial cells and sometimes macrophages. They attach via an adhesin, rickettsial outer membrane protein A, and are internalized where they persist as cytoplasmically free organisms. Rickettsia massiliae is a member of the spotted fever group of the Rickettsiales and has been isolated from ticks in Europe and Africa. Rickettsia massiliae does not appear to cause disease in humans.