Rickettsia conorii

From IDWiki
Rickettsia conorii
  • A tickborne rickettsial species that causes boutonneuse fever, the most severe form of rickettsial spotted fever next to Rocky Mountain spotted fever
  • Also known as Marseilles fever, Mediterranean spotted fever, Kenya tick typhus, Israeli tick typhus, Astrakhan spotted fever, and Indian tick typhus

Background

Microbiology

  • Species of Rickettsia within the spotted fever group

Life Cycle

  • Maintained transovarially within the tick species

Epidemiology

  • Transmitted by Rhipicephalus sanguineus ticks
  • Founds in India, Pakistan, Israel, Russia, Georgia, Bulgaria, Turkey, Ukraine, Ethiopia, Kenya, South Africa, Morocco, and southern Europe
  • More cases occur during the warm months (July through September in the Mediterranean)

Clinical Manifestations

  • Incubation period of 7 days
  • Initial symptoms include fever, myalgias, and headache
  • Often has an eschar at the site of tick bit inoculation ("tache noir"), but not always
  • Petechial rash, GI symptoms, obtundation, tachypnea, hepatomegaly, leukocytosis, coagulopathy, AKI, bilirubin elevation, AST elevation, and CK elevation
  • Procoagulant, and 10% develop DVT
  • Can present as acute pancreatitis
  • Can be quite severe with higher mortality than others in the spotted fever group

Management

  • First-line: doxycycline 100 mg po bid for 7 days (at least 5-7 days and resolution of symptoms for 3 days)
    • May be able to shorten to a single day of two doses of 200 mg each in one small study
    • Could use minocycline
  • Ciprofloxacin is associated with a more severe course and should be avoided
  • Azithromycin or clarithromycin may be considered in pregnant women or children