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Volume 2, Number 1—January 1996

Emergence of the Ehrlichioses as Human Health Problems

David H. Walker* and J. Stephen Dumler†
Author affiliations: *Department of Pathology, University of Texas Medical Branch at Galveston; †Department of Pathology, The Johns Hopkins Medical Institutions

Main Article

Table 1

Six related clusters of obligately intracellular gram-negative bacteria determined by 16S rRNA comparisons

Prototype species of the cluster Other genera within genetic confines Vector
I. Ehrlichia canis Cowdria Ticks
 II. E. phagocytophila Anaplasma Ticks
III. E. sennetsu Neorickettsia Fish flukes
IV. Wolbachia pipientis Rhinocyllus, Nasonia incompatibility intracellular symbionts Insects
V. Rickettsia rickettsii None Ticks, fleas, mites, lice
VI. Orientia tsutsuga-mushi* (R. tsutsugamushii) None Chiggers

* Proposed new taxonomic designation (20).

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