1Department of Fishery Pathology and Microbiology, Faculty of Fishery Sciences, W. B. University of Animal and Fishery Sciences, Panchasayar, Kolkata - 700 094 (W.B.).
2Department of Zoology, Lucknow University, Uttar Pradesh.
Several advanced technologies are now being adopted for efficient production and better health management practices in aquaculture, with prevention and control of fish diseases as the focal theme. The modern diagnostic assays are based on interactions of certain important biomolecules of the pathogens such as antigen, nucleic acids etc. following their isolation, purification and characterization for preparing suitable diagnostic and/or prophylactic tools. Enzymes, radioisotopes and fluorescent dyes are used in certain advanced serological techniques like enzyme-linked immunosorbent assay (ELISA), western blotting, radioimmunoassay and fluorescent antibody test. Several ELISA systems employing monoclonal antibodies to fish pathogens have been described. The key to gene-based (nucleic acid-based) diagnosis is the nucleic acid probe and, the nucleic acid hybridization methods have been found to be extremely useful for detection of prawn/shrimp pathogens, particularly, the viruses that are difficult to isolate and purify due to non availability of prawn/shrimp cell lines. During recent years, several standard and modified polymerase chain reaction protocols are available for diagnosis of infectious pathogens of fish and shrimp. At present, most of the vaccines against fish pathogens are produced empirically, however, efforts are on to prepare these by using gene-based technologies. Various immunobiochemical and molecular techniques used in aquaculture for diagnostic and prophylactic purposes have been reviewed in this article.
