Iridoviruses belonging to the family Iridoviridae and genus Megalocytivirus cause systemic disease in fishes. It responsible for high mortality of cultured marine and freshwater fishes. Current detection kits are not field deployable and often require expensive instrumentation and technical expertise to perform the assay. There is a need for a rapid, on-site and user-friendly test method to detect iridoviral pathogen in farm settings.
In the present study, optical immuno assay (OIA) method was developed to detect iridoviral infection in fish. The kit comprises of sample processing (tissue and blood) gadgets, and a disposable test device that can be deployed for on-site detection. Irido-OIA kit has the ability to detect pathogen and host response in a single test. This will help in post vaccine monitoring of fishes for their serological response/protective immunity and as well pathogen presence.
Fish samples (n=65) were analysed for the presence of iridoviruses in suspected fish samples and compared with the gold standard PCR method. The irido-OIA kit was able to detect 5x103 viral particles per millilitre of processed tissue sample, with an overall sensitivity and specificity of 91.6% and ~98% respectively. Further, the performance of kit will be evaluated with more field samples. Moreover, the operational advantages of the Irido-OIA kit include field deployability, rapid detection, user friendliness with less logistic load, and visual read-out.