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