Establishment and evaluation of an indirect immunofluorescence assay for the detection of salmonid alphavirus.

Salmonid alphaviruses (SAV) severely infect farmed salmonids and rainbow trout. Owing to the recent increase in fish import trade, several SAV unreported countries, such as China, may face serious threat of this infection. Thus, it is necessary to develop efficient detection methods for the prevention and diagnosis of SAV infection. In this study, we selected a conserved segment of the SAV E1 protein as a target immunogen for the preparation of monoclonal antibodies (mAbs) specific to SAV. A sensitive indirect immunofluorescence (IF) method was developed using 26E9C2 mAb that detected E1 protein and identified subtypes 1, 2 and 5 of SAV. Thus, this assay provides a sensitive and specific detection method, and an improved technical support for the clinical diagnosis and epidemiological study of SAV.

SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, we successfully prepared two monoclonal antibodies (mAbs) against three subtypes of salmonid alphavirus (SAV), and established an indirect immunofluorescence assay that can be used to diagnose and prevent SAV from entering SAV unreported countries, such as China, through international trade. The application of this method will contribute to controlling SAV infection and reducing economic losses.