Rickettsia Prowazekii (RP)

Rickettsia prowazekii is a species of gram-negative, alphaproteobacteria, obligate intracellular parasitic, aerobic Bacillus bacteria that is the etiologic agent of epidemic typhus, transmitted in the feces of lice. In North America, the main reservoir for R. prowazekii is the flying squirrel. R. prowazekii is often surrounded by a protein microcapsular layer and slime layer; the natural life cycle of the bacterium generally involves a vertebrate and an invertebrate host, usually an arthropod, typically the human body louse. he genome of R. prowazekii is reduced, being about 1Mb in size and encoding 834 proteins. Some strains encode 866 proteins. That is, they do not encode all the proteins required to live on their own. Missing activities have to be provided by its host, a eukaryotic cell. For this reason, R. prowazekii has sometimes been regarded as a model for the intracellular bacterial ancestor of mitochondria.