Book contents
- Frontmatter
- Contents
- Preface
- Contributors
- Part I Clinical Syndromes – General
- Part II Clinical Syndromes – Head and Neck
- Part III Clinical Syndromes – Eye
- Part IV Clinical Syndromes – Skin and Lymph Nodes
- Part V Clinical Syndromes – Respiratory Tract
- Part VI Clinical Syndromes – Heart and Blood Vessels
- Part VII Clinical Syndromes – Gastrointestinal Tract, Liver, and Abdomen
- Part VIII Clinical Syndromes – Genitourinary Tract
- Part IX Clinical Syndromes – Musculoskeletal System
- Part X Clinical Syndromes – Neurologic System
- Part XI The Susceptible Host
- Part XII HIV
- Part XIII Nosocomial Infection
- Part XIV Infections Related to Surgery and Trauma
- Part XV Prevention of Infection
- Part XVI Travel and Recreation
- Part XVII Bioterrorism
- Part XVIII Specific Organisms – Bacteria
- Part XIX Specific Organisms – Spirochetes
- Part XX Specific Organisms – Mycoplasma and Chlamydia
- Part XXI Specific Organisms – Rickettsia, Ehrlichia, and Anaplasma
- 168 Rickettsial Infections
- 169 Ehrlichiosis and Anaplasmosis
- Part XXII Specific Organisms – Fungi
- Part XXIII Specific Organisms – Viruses
- Part XXIV Specific Organisms – Parasites
- Part XXV Antimicrobial Therapy – General Considerations
- Index
168 - Rickettsial Infections
from Part XXI - Specific Organisms – Rickettsia, Ehrlichia, and Anaplasma
Published online by Cambridge University Press: 05 March 2013
- Frontmatter
- Contents
- Preface
- Contributors
- Part I Clinical Syndromes – General
- Part II Clinical Syndromes – Head and Neck
- Part III Clinical Syndromes – Eye
- Part IV Clinical Syndromes – Skin and Lymph Nodes
- Part V Clinical Syndromes – Respiratory Tract
- Part VI Clinical Syndromes – Heart and Blood Vessels
- Part VII Clinical Syndromes – Gastrointestinal Tract, Liver, and Abdomen
- Part VIII Clinical Syndromes – Genitourinary Tract
- Part IX Clinical Syndromes – Musculoskeletal System
- Part X Clinical Syndromes – Neurologic System
- Part XI The Susceptible Host
- Part XII HIV
- Part XIII Nosocomial Infection
- Part XIV Infections Related to Surgery and Trauma
- Part XV Prevention of Infection
- Part XVI Travel and Recreation
- Part XVII Bioterrorism
- Part XVIII Specific Organisms – Bacteria
- Part XIX Specific Organisms – Spirochetes
- Part XX Specific Organisms – Mycoplasma and Chlamydia
- Part XXI Specific Organisms – Rickettsia, Ehrlichia, and Anaplasma
- 168 Rickettsial Infections
- 169 Ehrlichiosis and Anaplasmosis
- Part XXII Specific Organisms – Fungi
- Part XXIII Specific Organisms – Viruses
- Part XXIV Specific Organisms – Parasites
- Part XXV Antimicrobial Therapy – General Considerations
- Index
Summary
The definition of the Rickettsiaceae family has changed since the mid-1980s on the basis of new genetic tools, allowing the discovery of new species and the reclassification of other species. The Rickettsiaceae are aerobic, small, gram-negative coccobacilli that are obligate intracellular parasites of eukaryotic cells. The Rickettsiales now consist of the genus Rickettsia, the new genus Orientia, and the Ehrlichia group. There are three groups of Rickettsiae based on clinical presentation: the spotted fever group, the typhus group, and scrub typhus. Coxiella burnetii, the agent that causes Q fever, is covered in this chapter but is now classified in the γ-proteobacteria group, together with Legionella and Francisella tularensis.
The pathogenesis of illness due to the Rickettsiae is vasculitis. The rickettsiae proliferate in the endothelial lining cells of the small arteries, capillaries, and veins. Erhlichiae invade and proliferate in their target cells of the hematopoietic and lymphoreticular systems, whereas in Q fever the organisms are inhaled and proliferate in the lungs, causing inflammation and bacteremic seeding of other organs, particularly the liver. All of the important rickettsial infections are vectorborne, whereas Q fever usually results from inhalation of dust contaminated by the birth fluids of domestic ungulates.
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- Chapter
- Information
- Clinical Infectious Disease , pp. 1167 - 1172Publisher: Cambridge University PressPrint publication year: 2008