1 / 52

Rickettsia

Rickettsia. Group of bacteria that are fastidious, obligate intracellular pathogens They are pleomorphic & coccobacillary • The organisms will not show up on Gram stain, but can be seen when either Gimenez or Giemsa stains are used. Why Rocky Mountain Spotted Fever?. Prototype rickettsiosis

gilon
Download Presentation

Rickettsia

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Rickettsia • Group of bacteria that are fastidious, obligate intracellular pathogens • They are pleomorphic & coccobacillary • The organisms will not show up on Gram stain, but can be seen when either Gimenez or Giemsa stains are used

  2. Why Rocky MountainSpotted Fever? • Prototype rickettsiosis • Main reason for deaths?

  3. Etiology: Invertebrates 1. Rickettsia rickettsiae 2. Ticks (tolerate infection) • Dermacentor andersonii, D. variabilis (“hard”) • Transstadial, transovarial transmission

  4. Etiology Microbe R. rickettsii Vector Tick Reservoir Rodents Host Intruder

  5. Person • Outdoor activity • Peak age 5-9 • Mortality highest in elderly

  6. Development of illness • Inoculation • Rickettsemia • Endothelial localization • Vasculitis

  7. Clinical recognition • Rash • Fever • Headache • Other

  8. Fever and headache • Fever • 102 to 105 degrees • 2 to 3 weeks without treatment • Headache: severe

  9. Clinical recognition • Rash • Fever • Headache • Other

  10. Clinical recognition • Rash • Fever • Headache • Other

  11. Laboratory diagnosis • Skin biopsy: immunofluorescent stain • Serology • Weil-Felix archaic • Immunofluorescent antibody • No growth on routine culture

  12. Prevention • Vector control impractical • Vaccine unavailable • So . . . caution outdoors • Long clothing • Skin inspection

  13. Rocky Mountain Spotted Fever • Physician suspicion crucial • R. rickettsii, ticks • Not just Rockies • Vasculitis • Rash, fever, headache • Doxycycline, look for ticks

  14. Rickettsiae & spirochetes • Rocky Mountain Spotted Fever • Rickettsial biology • Other rickettsioses • Spirochetes

  15. Order Rickettsiales • Family Rickettsiaceae • Tribe Rickettsiae • Genus Rickettsia • Genus Coxiella • Genus Rochalimaea • Family Bartonellaceae

  16. Spotted Fever Group • Rocky Mountain spotted fever – Rickettsia rickettsii • Rickettsial pox – Rickettsia akari • Canadian typhus – Rickettsia canada • Mediterranean spotted fever – Rickettsia conorii • Siberian tick typhus – Rickettsia siberica • Queensland tick typhus – Rickettsia australis • Murine typhus (also known as endemic typhus and fleaborne typhus) – Rickettsia mooseri (typhi) • • Epidemic typhus (also known as Brill- Zinsser disease and louseborne typhus) – Rickettsia prowazekii • • Scrub typhus (or Chigger fever) – Rickettsia tsutsugamushi

  17. Rickettsial groups • Spotted fever group • Rocky Mountain Spotted Fever • Other spotted fevers • Rickettsialpox • Typhus group • Epidemic typhus, Brill-Zinsser • Murine, scrub typhus

  18. Typical rickettsial illness • Inoculation eschar (exception: Rocky Mountain Spotted Fever) • Rickettsemia • Endothelial growth • Vasculitis • 1-2 week incubation • Rash, fever, headache

  19. Rickettsial diagnosis • Must suspect clinically • Immunoflorescent stained skin biopsy • Weil-Felix passé • Serology usually (but delay in getting results) • Isolation hazardous • Rule out others

  20. Rickettsial control • Public health • Reporting • Vector/reservoir • No vaccines

  21. Rickettsial diseases other than Rocky Mountain Spotted Fever • Other spotted fevers (in other parts of world) • Rickettsialpox (urban, from mice and mites) • Typhus group (epidemic typhus from lice)

  22. Other rickettsioses • Vector (often tick) • Eschar, rickettsemia • Vasculitis, serologic test • Includes spotted fevers, rickettsialpox, typhus group

  23. Typical Eschar at Tick Bite Site

  24. Rickettsiae & spirochetes • Rocky Mountain Spotted Fever • Rickettsial biology • Other rickettsioses • Spirochetes

  25. Vincent’s infection/Trench mouthNecrotizing ulcerative gingivitis • Synergistic gum infection • Occurs in poor oral hygiene, malnutrition, immunocompromise • Penicillin, oral hygiene

  26. B. recurrentis Lice Human-lice E. Africa, Andes Borrelia spp Ornithodoros tick Human intruder Worldwide: High, warm, humid Relapsing FeverEpidemic Endemic

  27. Relapsing fever pathogenesis • Spirochetemia • Sequestration • Antigenic modification • Widespread (liver, spleen, CNS, heart, GI, kidney)

  28. Relapsing fever presentation • Abrupt fever, malaise, headache • Arthralgia, cough, photophobia • Conjunctival suffusion • Petechiae • Abdominal tenderness

  29. Relapsing fever • Recovery in 3-6 days • Relapse in 7-10 days • Untreated, 40% die • Blood smear positive 70% • Tetracycline, chloramphenicol

  30. Lyme disease, United States

  31. Lyme disease cases by month, US, 1999

  32. Erythema chronicum migrans

  33. Lyme diagnosis and treatment • Clinical, with special serology • Treatment depends on stage • Doxycycline, amoxicillin, cefuroxime • IV penicillin or ceftriaxone (later)

  34. Tick repellent • DEET • Skin, clothing • CNS toxicity (directions) • Permethrin: Clothing

  35. Key points: Lyme disease • Tickborne B. burgdorferi • Local: Erythema migrans • Dissem: Heart, nerve, joint • Persist: Fatigue, joint • Doxycycline, ceftriaxone

  36. Frontiers of prevention • Vaccine: Withdrawn • Tick avoidance

  37. Many spirochetes tickborne • Not tickborne • Syphilis: Sex • Leptospirosis: Animal urine; early conjunctival suffusion, later liver & kidneys • Tickborne: Borrelia relapsing fever, change antigens & relapse

  38. Lyme (& Syphilis) Initial rash: Erythema chron. mig. 2º stage: Nerves, heart, joints Late stage: Arthritis, fatigue Treatment: Penicillin, tetracycline Spirochetal disease parallels

  39. Rickettsia and spirochetes • Rocky Mountain Spotted Fever • Headache, rash, fever • Tickborne • No growth on routine culture • Doxycycline

More Related