Field‐Usable Lateral Flow Immunochromatographic Assay for Rapid Detection of Infectious Haematopoietic Necrosis Virus (IHNV)

ABSTRACT A lateral flow immunochromatographic assay (LFIA) was developed for the rapid detection of infectious haematopoietic necrosis virus (IHNV, genogroups JRt‐N and JRt‐S) in rainbow trout ( Oncorhynchus mykiss ). The assay utilises the monoclonal antibody (mAb) IHNV‐3, which serves as both the detector antibody in a colloidal gold‐mAb conjugate and the capture antibody on the test line. The LFIA strip demonstrated a detection limit ranging from 10 5.05 to 10 5.8 TCID 50 /100 μL for six IHNV isolates (genogroups JRt‐N and JRt‐S) and showed no cross‐reactivity with other fish viruses. Field validation using spleen samples from 81 IHNV‐infected and 102 non‐infected rainbow trout revealed a specificity of 100%, a sensitivity of 97.5%, and an overall diagnostic effectiveness of 98.9%. These results highlight the LFIA strip as a reliable tool for the rapid (within 10 min) on‐site detection of IHNV in rainbow trout at aquaculture facilities.