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Volume 23, Number 8—August 2017

Serologic Evidence of Powassan Virus Infection in Patients with Suspected Lyme Disease1

Holly M. FrostComments to Author , Anna M. Schotthoefer, Angela M. Thomm, Alan P. Dupuis, Sue C. Kehl, Laura D. Kramer, Thomas R. Fritsche, Yvette A. Harrington, and Konstance K. Knox
Author affiliations: Marshfield Clinic Research Foundation, Minocqua, Wisconsin, USA (H.M. Frost); Marshfield Clinic Research Foundation, Marshfield, Wisconsin, USA (H.M. Frost, A.M. Schotthoefer, T.R. Fritsche); Coppe Laboratories, Waukesha, Wisconsin, USA (A.M. Thomm, Y.A. Harrington, K.K. Knox); New York State Department of Health, Slingerlands, New York, USA (A.P. Dupuis II, L.D. Kramer); Medical College of Wisconsin, Milwaukee, Wisconsin, USA (S.C. Kehl)

Main Article

Table 1

TBEV-C and Borrelia burgdorferi serologic test results and POWV RT-PCR test results of patients with positive POWV IFA assay results, Wisconsin, July–August 2015*

Patient no. TBEV-C IgM EIA TBEV-C IgG EIA POWV IgM IFA assay† POWV IgG IFA assay‡ POWV PRNT§ POWV RT-PCR¶ B. burgdorferi#
Suspected TBD patients
1**†† + +
2†† + + + IgG and IgM
3†† + + IgG and IgM
4†† + + IgG and IgM
5 + + +
6 + + IgG and IgM
7 + + IgM
8 + + + + + IgG and IgM


IgG and IgM
Patients screened by chemical methods
1c + + NA
2c†† + + + + NA

*EIA, enzyme immunoassay; IFA, immunofluorescence antibody; NA, not assayed; POWV, Powassan virus; PRNT, plaque reduction neutralization test; PRNT90, >90% plaque reduction neutralization test; RT-PCR, reverse transcription PCR; TBD, tickborne disease; TBEV-C, tick-borne encephalitis virus complex.
†Titers >1:20 were considered positive.
‡Titers >1:40 were considered positive.
§Positive if sample had a PRNT90 titer.
¶Not performed in specimens with a negative POWV IgM IFA assay result.
#Samples were screened by EIA and followed up by Western blot.
**Cross-reactivity on POWV IgG IFA assay is consistent with a history of West Nile virus infection.
††Clinical data were available.

Main Article

1Preliminary results from this study were presented at IDWeek; October 26–30, 2016; New Orleans, Louisiana, USA.

Page created: July 17, 2017
Page updated: July 17, 2017
Page reviewed: July 17, 2017
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