General Information: This organism was originally isolated from ticks in a field study on tick-transmitted diseases of small mammals in Canada. Member of the typhus group of Rickettsiales. 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 canadensis was originally thought to be a member of the typhus group of Rickettsiales, however, it is now thought to represent a distict group with the rickettsia.