Development of an immuno‐based colorimetric assay for white spot syndrome virus

White spot syndrome virus ( WSSV ) is a major cause of infectious disease in cultured shrimp. A fast and reliable method for detecting and monitoring the amount of WSSV during farming would be extremely useful. This work describes a sandwich immunoassay that uses anti‐ GST ‐ VP 26, a WSSV ‐binding protein ( WBP ), and modified streptavidin magnesphere paramagnetic particles ( SMPP s) to develop the technique. The WBP was immobilized on SMPP s and later bound to different copies of WSSV . The binding was detected using anti‐ GST ‐ VP 26 conjugated to alkaline phosphatase. This enzymatic reaction successfully changed the test solution to a concentration‐dependent yellow color that was measured at 405 nm. The sensitivity of this method was between 1.6 × 10 4 and 1.6 × 10 7 copies µL −1 of WSSV . In this study, the color for detection and semiquantitative analysis is easily observed and measured and can lead to the development of a test kit for screening WSSV during shrimp farming.