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Updated: Feb 15, 2026

An Electroporation Method to Transform Rickettsia spp. with a Fluorescent Protein-Expressing Shuttle Vector in Tick Cell Lines
Published on: October 11, 2022
Rickettsia parkeri infections diagnosed by eschar biopsy, Virginia, USA
Pamela Kelman1, Chelsea Wright Thompson2, Wayne Hynes2
1Virginia Department of Health, Richmond, VA, USA.
Background:
Infection with Rickettsia parkeri is an emerging tick-borne illness, often accompanied by fever and an eschar at the site of tick attachment. We present three cases of R. parkeri in Virginia residents.
Case Presentations:
Case 1 presented initially afebrile, failed to seroconvert to rickettsial antigens, and was diagnosed by DNA testing of the eschar. Case 2 presented febrile with eschar, no serologies were performed, and was diagnosed by DNA testing of the eschar. Case 3 presented febrile with eschar, serologies were negative for rickettsial antigens, and was diagnosed by DNA testing of the eschar.
Conclusion:
DNA testing of eschars represents an under-utilized diagnostic test and may aid in cases where the diagnosis is not made clinically.
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