Rapid Antigen Tests for Dengue Virus Serotypes and Zika Virus in Patient Serum

Abstract

The recent Zika virus (ZIKV) outbreak demonstrates that cost-effective clinical diagnostics are urgently needed to detect and distinguish viral infections to improve patient care. Unlike dengue virus (DENV), ZIKV infections during pregnancy correlate with severe birth defects, including microcephaly and neurological disorders. Because ZIKV and DENV are related flaviviruses, their homologous proteins and nucleic acids can cause cross reactions and false positive results in molecular, antigenic, and serologic diagnostics. We report here the characterization of monoclonal antibody pairs that have been translated into rapid immunochromatography tests to specifically detect the viral nonstructural 1 (NS1) protein antigen and distinguish the four DENV serotypes and ZIKV without cross reaction. To complement visual test analysis and remove user subjectivity in reading test results, image processing and data analysis were used for data capture and test result quantification. Using a 30 µl serum sample, the sensitivity and specificity values of the DENV serotypes 1–4 tests and the pan DENV test, which detects all four dengue serotypes, ranged from 0.76 to 1.00. Sensitivity/specificity for the ZIKV rapid test was 0.81/0.86 using a 150 µl serum input. Serum ZIKV NS1 protein concentrations were approximately tenfold lower than corresponding DENV NS1 concentrations in infected patients; moreover, ZIKV NS1 protein was not detected in PCR-positive patient urine samples. Our rapid immunochromatography approach and reagents have immediate application in differential clinical diagnosis of acute ZIKV and DENV cases, and the platform can be applied toward developing rapid antigen diagnostics for emerging viruses.