Rickettsia prowazekii str. Madrid E

Rickettsia prowazekii is an obligate intracellular Gram negative parasite. It is the causative agent of epidemic typhus which infected 20-30 million people in the wake of the First World War and killed another few million following the Second World War. The plague of Athens in 430 BC was probably a typhus epidemic, and three million Europeans and Russians died from typhus between 1918 and 1922.Because it is the descendant of free-living organisms R. prowazekii is of interest as being possibly the closest extant relative of the ancestor to mitochondria. As an intracellular parasite in eukaryotic cells, the Rickettsia genome, like that of mitochondria, shows the effects of the evolutionary forces reducing its complexity and insight into adaptations of the obligate intracellular lifestyle.The bacterium is named after two typhus researchers who died of the disease in the early 20th century, H.T. Ricketts and S.J.M. Prowazek.(From http://www.ebi.ac.uk/2can/genomes/bacteria.html) (BacMap)