Emerging Tickborne Diseases – 5/4/2017

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  • Christopher Paddock, M.D., M.P.H.T.M., Medical Officer and Activity Chief
  • Kerry Padgett, Ph.D.– Supervising Public Health Biologist


Part 1: Expanding recognition of Rickettsia parkeri rickettsiosis in the United States 

Since the initial recognition of Rickettsia parkeri as a tick-borne pathogen of humans  in 2004, approximately 40 cases of this spotted fever group rickettsiosis have been identified throughout nine southeastern states and southern Arizona. The actual incidence of R. parkeri rickettsiosis is unknown, but it is likely that some, or possibly many, of the approximately 13,500 non-characterized cases of spotted fever reported in the United States during 2008-2012 were caused by R. parkeri. This presentation will summarize the clinical features, diagnosis, treatment, and distribution of this emerging tick-borne disease.

Part 2: Eco-epidemiology of an emerging tick-borne rickettsiosis: Pacific Coast tick fever

Rickettsia philipii, the etiologic agent of Pacific Coast tick fever (PCTF), is transmitted to people by the Pacific Coast tick, Dermacentor occidentalis. The Pacific Coast tick’s range, and thus potential for exposure to R. philipii, includes most of California, southern Oregon, and northern Baja California, Mexico. This presentation will describe clinical manifestations, diagnosis, and treatment of the 14 human cases reported to date in California and the known acarological risk factors for encountering PCTF.

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