Serological diagnosis of Zika virus (ZIKV) infection is challenging because of antigenic cross-reactivity with dengue virus (DENV). This study evaluated the accuracy of the Zika IgM antibody capture enzyme-linked immunosorbent assay (CDC Zika IgM MAC-ELISA) in differentiating between ZIKV and DENV infections. To determine sensitivity, we used acute- and convalescent-phase sera from 21 patients with RT-PCR-confirmed ZIKV infection. To determine specificity, we used acute- and convalescent-phase sera from 60 RT-PCR-confirmed dengue cases and sera from 23 blood donors. During the acute-phase of the illness, the assay presented a sensitivity of 12.5% (2/16) for samples collected 0–4 days post symptoms onset (DPSO), and of 75.0% (3/4) for samples collected 5–9 DPSO. During the convalescent-phase of the illness, the test sensitivity was 90.9% (10/11), 100% (2/2), and 0% (0/2) for samples obtained 12–102, 258–260, and 722–727 DPSO, respectively. Specificity for acute- and convalescent-phase samples from RT-PCR-confirmed dengue cases was 100% and 93.2%, respectively. Specificity for blood donor samples was 100%. The assay is an accurate method for Zika serological diagnosis and proved to be reliable for use during surveillance and outbreak investigations in settings where ZIKV and DENV cocirculate.
Bibliographical noteFunding Information:
Funding: This study was supported by the Brazilian National Council for Scientific and Technological Development (grant 550160/2010-8 to MGR, grants 400830/2013-2 and 440891/2016-7 to GSR, grant 439967/2016-3 to RK, and scholarships to MGR and GSR); the Bahia Foundation for Research Support (grant PNX0010/2011 to MGR, grants PPP0055/2011, JCB0020/2013, PET0026/2013, APP0044/2016, and PET0022/2016 to GSR); and the Coordination for the Improvement of Higher Education Personnel, Brazilian Ministry of Education (grant 88887.130746/2016-00 to GSR and scholarships to MMP, LM, MK and LCJN).
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- CDC Zika MAC-ELISA
- Diagnostic accuracy
- Enzyme-linked immunosorbent assay
- Sensitivity and specificity
- Zika virus