• 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. (wikipedia.org)
  • Rickettsia typhi is a small (0.3 by 1 (m), obligately intracellular bacterium. (bcm.edu)
  • Phylogenetically a member of the alpha subgroup of Proteobacteria, R. typhi is along with R. prowazekii considered to be a typhus group rickettsia. (bcm.edu)
  • Many more metabolic studies have been performed with R. prowazekii than R. typhi . (bcm.edu)
  • Rickettsia typhi evolved in close association with its arthropod vectors, various species of fleas. (bcm.edu)
  • Thus R. typhi do not spread effectively to other cells until their intracellular growth by binary fission results in accumulation of such large quantities of cytoplasmic bacteria that the infected host cell bursts, releasing large quantities of rickettsiae. (bcm.edu)
  • Rickettsia typhi are highly infectious, including by aerosol inhalation. (bcm.edu)
  • Rickettsial pathogens transmitted by arthropods other than ticks, including fleas ( Rickettsia typhi ), lice ( Rickettsia prowazekii ), and mites ( Rickettsia akari ) are not included in this report. (cdc.gov)
  • A form of R. prowazekii that exists in the feces of arthropods remains stably infective for months. (wikipedia.org)
  • Vaccines against R. prowazekii were developed in the 1940s, and were highly effective in reducing typhus deaths among U.S. soldiers during World War II. (wikipedia.org)
  • In general rickettsiae have evolved numerous characteristics that take advantage of their intracytosolic niche to acquire ATP, amino acids, cytoplasmic forms of sugars, and other metabolic products of the host cell. (bcm.edu)
  • Rickettsia felis was successfully isolated in cell culture from all three cat-flea pools. (biomedcentral.com)
  • 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. (wikipedia.org)
  • Rickettsiae are Gram-negative, obligate, intracellular alpha-proteobacteria in the family Rickettsaceae and order Rickettsiales . (medscape.com)
  • R. prowazekii also appears to be the closest free-living relative of mitochondria, based on genome sequencing. (wikipedia.org)
  • For this reason, R. prowazekii has sometimes been regarded as a model for the intracellular bacterial ancestor of mitochondria. (wikipedia.org)
  • The simplest explanation of these data is that mitochondria evolved from a planktonic marine alphaproteobacterial lineage that participated in multiple inter-specific cell colonization events, in some cases yielding parasitic relationships, but in at least one case producing a symbiosis that characterizes modern eukaryotic life. (nature.com)
  • The genome of R. prowazekii is reduced, being about 1Mb in size and encoding 834 proteins. (wikipedia.org)
  • Rickettsiae are usually transmitted via arthropod vectors such as ticks, mites, lice and fleas. (medscape.com)
  • For example, Rickettsia prowazekii , the causative agent of epidemic typhus, is transmitted between humans by fleas and lice whereas Rickettsia typhi, which causes endemic typhus, is transmitted from rats to humans by the rat flea. (medscape.com)
  • Hard ticks ( Ixodidae ) have been identified as the main vectors of the spotted fever syndrome in humans, which is caused by approximately 20 different Rickettsia species, of which approximately half circulate in Europe ( Table 1 ). (medscape.com)
  • Many more Rickettsia species have been associated with ticks, but their potential for pathogenicity is still unknown. (medscape.com)
  • Routine serological techniques cannot distinguish among different rickettsiae species of the spotted group, and it is not always clear which Rickettsia species caused disease. (medscape.com)
  • Immunity following recovery from infection with, or by immunization against, R. prowazekii is lifelong in most cases. (wikipedia.org)