Abstract
Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These infections are among the oldest known diseases transmitted by vectors. In the last three decades there has been a rapid increase in the recognition of this disease complex. This unusual expansion of information was mainly caused by the development of molecular diagnostic techniques that have facilitated the identification of new and previously recognized rickettsiae. A lot of currently known bacteria of the genus Rickettsia have been considered nonpathogenic for years, and moreover, many new species have been identified with unknown pathogenicity. The genus Rickettsia is distributed all over the world. Many Rickettsia species are present on several continents. The geographical distribution of rickettsiae is related to their vectors. New cases of rickettsioses and new locations, where the presence of these bacteria is recognized, are still being identified. The variety and rapid evolution of the distribution and density of ticks and diseases which they transmit shows us the scale of the problem. This review article presents a comparison of the current understanding of the geographic distribution of pathogenic Rickettsia species to that of the beginning of the century.
Highlights
Tick-borne rickettsioses are caused by obligate intracellular Gram-negative bacteria belonging to the spotted fever group (SFG) of the genus Rickettsia
A lot of currently known bacteria of the genus Rickettsia have been considered nonpathogenic for years, and many new species have been identified with unknown pathogenicity
There are 25 known pathogenic species of bacteria belonging to the genus Rickettsia, most of which have been described for the first time in the last 30 years (Figure 1)
Summary
Tick-borne rickettsioses are caused by obligate intracellular Gram-negative bacteria belonging to the spotted fever group (SFG) of the genus Rickettsia. These infections are among the oldest known diseases transmitted by vectors [1]. In the last three decades there has been a rapid increase in the recognition of this disease complex This unusual expansion of information was mainly caused by the development of molecular diagnostic techniques that have facilitated the identification of new and previously recognized rickettsiae. A lot of currently known bacteria of the genus Rickettsia have been considered nonpathogenic for years, and many new species have been identified with unknown pathogenicity. There are several classifications of bacteria of the genus Rickettsia, but the most commonly used one divides them into four groups: spotted fever group (SFG), typhus group (TG), the Rickettsia bellii group, and the Rickettsia canadensis group [1,2]
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