Fievre boutonneuse was first described in 1910 by Conor and Bruch. Rickettsia conorii has been the most pathogenic and geographically widespread of Old World pathogens.Much like the case of Rickettsia rickettsii in the Americas, however, it was too often assumed to be the only rickettsial pathogen. In 2005 Rickettsia conorii classification was amended to include 4 subspecies, with the type strain Malish becoming R. conorii subsp.conorii. Joining this species are the agents of Astrakhan fever (R. conorii subsp. caspia), Israeli spotted fever (R. conorii subsp. israelensis) and Indian tick typhus (R. conorii subsp. indica). Molecular tools have also demonstrated other pathogenic species in the regions historically associated with Rickettsia conorii.