Query: NC_010793:357000 Orientia tsutsugamushi str. Ikeda, complete genome
Lineage: Orientia tsutsugamushi; Orientia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: This organism is the causative agent of scrub typhus, and like other members of the Rickettsiales is an obligate intracellular organism. Scrub typhus, which occurs in rural and agricultural areas, is one of the most common infectious diseases in southeast Asia where an estimated 1 million cases occur each year. Many cases are mild, but if left untreated, a variety of serious illnesses can arise and fatality rates can range from 1-35%. Transmission occurs via an insect vector through the bite of the larval trombiculid mite (chiggers). The bacterium is transmitted transovarially in mites (from females to their offspring).
Subject: NC_006142:140853 Rickettsia typhi str. Wilmington, complete genome
Lineage: Rickettsia typhi; Rickettsia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: This genus, like other Rickettsial organisms such as Neorickettsia and Anaplasma, is composed of obligate intracellular pathogens. The latter is composed of two organisms, Rickettsia prowazekii and Rickettsia typhi. The bacteria are transmitted via an insect, usually a tick, to a host organism, in this case humans, 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. Transovarial transmission (from mother to offspring) occurs in the invertebrate host. Rickettsia typhi causes murine typhus and is an obligate intracellular pathogen that infects both the flea vector and hosts such as human, rat, and mouse. In the flea vector, the bacterium penetrates the gut epithelial barrier and is found in the feces which become infective.