Rickettsiae are obligate intracellular bacteria that strike terror into epidemiologists and make students sweat during exams. They are transmitted via arthropod bites or feces and cause acute febrile illnesses characterized by a distinctive rash and vascular endothelial damage.
In this section, we will analyze the main representatives of the group. You will study the causative agents of classical epidemic and murine (endemic) typhus, get acquainted with the extensive group of tick-borne rickettsioses, and learn about the exotic tsutsugamushi fever.
In classes and tests, examiners most frequently ask about transmission chains (louse–human, flea–rat, tick–rodent), features of intracellular parasitism, and the pathogenesis of generalized vasculitis. Pay special attention to the indirect hemagglutination assay (IHA), the indirect immunofluorescence assay (IFA), and Brill-Zinsser disease — these are favorite questions to test clinical thinking.