R. Rickettsia

• What are the characteristics of Rickettsia?


  • Non-motile
  • aerobic
  • gram-negative
  • lives in cytosol of host cell
• What type of staining is usually used for visualization?

  • Hematoxylin
  • Eosin (H&E)
• What are the three Rickettsia species that cause most human infections?


  • R. rickettsii and R. typhii: continuously released via exocytosis
  • R. prowazekii: fills up the host cells until the host cell lyses, releasing the parasites (keeps reproducing inside host cells)
• How are all three Rickettsia transmitted?


  • arthropod vectors (lice, ticks, mites)
  • Each Rickettsial species is transmitted by different vectors