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
9††	+	–	+	–	–	–	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.