Query: NC_016930:943000 Rickettsia philipii str. 364D chromosome, complete genome
Lineage: Rickettsia philipii; Rickettsia; Rickettsiaceae; Rickettsiales; Proteobacteria; Bacteria
General Information: Rickettsiae are obligate intracellular Gram-negative bacteria mostly found in arthropods, some of which cause mild to severe diseases in humans. Spotted fever group rickettsiae (SFGR) cause disease in humans. R .philippi strain 364D, an SFGR, was isolated in 1966 from Dermacentor occidentalis ticks collected in Ventura county, California, and since then 364D has been detected in up to 11% of D. occidentalis from 8 California counties. It has now been recognized as causing eschar-associated illness.
Subject: NC_010673:479552 Borrelia hermsii DAH, complete genome
Lineage: Borrelia hermsii; Borrelia; Spirochaetaceae; Spirochaetales; Spirochaetes; Bacteria
General Information: This strain was isolated from a case of relapsing fever in western Washington, USA. Borrelia hermsii is the causative agent of tick-borne relapsing fever in the western United States and Canada. Borrelia then multiplies rapidly, causing a generalized infection throughout the tick. While feeding, the tick passes the organism into a mammalian host through its infectious saliva. Relapsing fever is characterized by a period of chills, fever, headache, and malaise, an asymptomatic period, followed by another episode of symptoms. This 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.