Volume 91, Issue 3
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



Rocky Mountain spotted fever (RMSF), a tick-borne zoonosis caused by , is among the deadliest of all infectious diseases. To identify the distribution of various genotypes of associated with fatal RMSF, we applied molecular typing methods to samples of DNA extracted from formalin-fixed, paraffin-embedded tissue specimens obtained at autopsy from 103 case-patients from seven countries who died of RMSF. Complete sequences of one or more intergenic regions were amplified from tissues of 30 (29%) case-patients and revealed a distribution of genotypes consisting of four distinct clades, including the Hlp clade, regarded previously as a non-pathogenic strain of . Distinct phylogeographic patterns were identified when composite case-patient and reference strain data were mapped to the state and country of origin. The phylogeography of is likely determined by ecological and environmental factors that exist independently of the distribution of a particular tick vector.


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  • Received : 10 Mar 2014
  • Accepted : 12 May 2014
  • Published online : 03 Sep 2014

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