Rickettsial diseases have affected humanity since the dawn of civilization. Despite the advent of effective antibiotic therapy, humans continue to be afflicted by rickettsial diseases, which still often go undiagnosed because of their protean clinical manifestations.

During the past decade, several major developments have occurred in rickettsiology. With the advent of the newly emerging infections caused by a number of rickettsias, the re-emerging of old pathogenic species of rickettsias that cause both old and new syndromes has helped redefine the level of rickettsial pathogenicity....