Query: NC_017044:178395 Rickettsia parkeri str. Portsmouth chromosome, complete genome
Lineage: Rickettsia parkeri; Rickettsia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: Animal pathogen in Mammalia (intracellular obligate). Rickettsiae are obligate intracellular Gram-negative bacteria mostly found in arthropods, some of which cause mild to severe diseases in humans. Rickettsia parkeri, a member of the spotted fever group Rickettsia (SFGR), was first isolated from the Gulf Coast tick, Amblyomma maculatum, in 1937. In 2004, the first confirmed human infection with R. parkeri was reported in a 40-year-old man from the Tidewater area of coastal Virginia. The agent was isolated in cell culture from an eschar biopsy specimen and designated the Portsmouth strain; recently, the first recognized case of tick bite-associated human infection was described.
Subject: NC_008710:386376 Borrelia turicatae 91E135, complete genome
Lineage: Borrelia turicatae; Borrelia; Spirochaetaceae; Spirochaetales; Spirochaetes; Bacteria
General Information: This strain was isolated in the USA from the soft tick Ornithodoros turicatae. Borrelia turicatae is the causative agent of tick-borne relapsing fever in the southwestern USA. Ticks become infected with Borrelia while feeding on an infected mammal, usually a rodent or squirrel. Borrelia then multiplies rapidly, causing a generalized infection throughout the tick. While feeding, the tick passes the spirochete into a mammalian host through its infectious saliva. Relapsing fever is characterized by period of chills, fever, headache, and malaise, followed by an asymptomatic, followed by another episode of symptoms. The cycle of relapsing is due to changes in the surface proteins of Borrelia, which allow it to avoid detection and removal by the host immune system. This antigenic variation is the result of homologous recombination of silent proteins into an expressed locus, causing partial or complete replacement of one serotype with another. These plasmids carry genes involved in antigenic variation and pathogenicity.