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

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 105.05 to 105.8 TCID50/100 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.