title: Emerging and re-emerging tick-transmitted rickettsial and ehrlichial infections.
abstract: Recently in the field of rickettsiology, an explosion of new isolates of pathogens have received species designation and new disease names, all of which have been relatively neglected by primary care and infectious disease physicians. A broad group of other tick-associated rickettsial and ehrlichial agents of unknown pathogenicity exist (eg, R amblyommii) that may cause confusion in interpreting serologic surveys or a single elevated antibody titer. Rickettsial and ehrlichial diseases are remarkable for their uniform susceptibility to doxycycline but are clinically difficult to distinguish from many viral infections and each another, and therefore misdiagnosis and failure to treat have unfortunate and sometimes tragic outcomes. Globally, many of these bacteria have been named but the genetic differences among them are often small, and many of their clinical manifestations may not be distinguishable diagnostically.
authors.affiliation: Department of Pathology, University of Texas Medical Branch, 301 University Boulevard, Galveston, TX 77555-0609, USA. dwalker@utmb.edu
authors.forename: David H
authors.initials: DH
authors.lastname: Walker
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Paddock
authors.forename: J Stephen
authors.initials: JS
authors.lastname: Dumler
mesh_terms: D000712:Anaplasmosis / Q000175:diagnosis / Q000453:epidemiology; D000907:Antibodies, Bacterial / Q000032:analysis; D000942:Antigens, Bacterial / Q000032:analysis; D001907:Boutonneuse Fever / Q000453:epidemiology; D021821:Communicable Diseases, Emerging; D016873:Ehrlichiosis / Q000175:diagnosis / Q000453:epidemiology*; D014943:Global Health; D006801:Humans; D012282:Rickettsia Infections / Q000175:diagnosis / Q000453:epidemiology*; D012373:Rocky Mountain Spotted Fever / Q000453:epidemiology; D014438:Typhus, Epidemic Louse-Borne / Q000175:diagnosis
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial