Chikungunya virus (CHIKV) is increasing in prevalence throughout the Western Hemisphere. Detection of anti-CHIKV antibodies is a rapid and readily accessible alternative to viral detection by nucleic acid testing or culture. Here, we evaluated the performance characteristics of the EUROIMMUN (Morris Plains, NJ) anti-CHIKV IgM and IgG EIAs in comparison to the Focus Diagnostics (San Juan Capistrano, CA) anti-CHIKV IgM and IgG immunofluorescence assays (IFAs).
The EUROIMMUN CHIKV IgM and IgG EIAs were evaluated with 71 serum samples previously characterized by the Focus Diagnostic IFAs. Normal donor serum samples (n=75) and serum samples (n=79) positive for IgM and/or IgG antibodies to Western Equine Encephalitis (WEE), St. Louis Encephalitis (SLE), California virus (CV), dengue virus (DV) and West Nile Virus (WNV) were evaluated by the EUROIMMUN CHIKV EIAs to assess specificity. Testing was performed per manufacturer instructions on the Triturus automated EIA analyzer (Grifols, USA. Miami, FL).
Compared to the Focus Diagnostics IFA, the EUROIMMUN CHIKV EIAs had a positive, negative and overall agreement of 94.1% (32/34), 97.3% (36/37) and 95.8% (68/71) for detection of IgM and/or IgG antibodies to CHIKV. Specifically, the EUROIMMUN CHIKV IgM and IgG EIA showed a positive, negative and overall agreement of 93.5% (29/31), 100% (40/40), 97.2% (69/71) and 73.1% (19/26), 97.8% (44/45) and 88.7% (63/71), respectively. Four of the 7 IgG EIA negative/IFA positive samples were also negative by the Florida Department of Health CHIKV IgG EIA. The IgM and IgG EIAs were negative in 98.7% (74/75) of normal donor sera and in all samples with antibodies to WEE, SLE, CV and WNV. Two samples with IgM antibodies to DV and one sample with IgG antibodies to DV were positive by the CHIKV IgM and IgG EIA, respectively.
The EUROIMMUN CHIKV IgM and IgG EIAs showed excellent negative and overall agreement with the Focus Diagnostics IFAs, which are only commercially available CHIKV serologic assays, aside from those through the CDC. The EUROIMMUN CHIKV IgM EIA also showed high positive agreement with the respective Focus IFA. When used in combination with exposure history and clinical presentation, the EUROIMMUN EIAs can be used as aids for the diagnosis of Chikungunya virus infection.
D. Jespersen, None
E. Theel, None