A COMPETITIVE ENZYME LINKED IMMUNOSORBENT ASSAY FOR DIAGNOSIS AND SEROMONITORING OF MICROBIAL INFECTIONS IN CULTURED FRESHWATER FISHES

摘要

A competitive ELISA was developed to diagnose the microbial infection of Indian major carps and other cultivable fish species. We found it suitable over other conventional serological tests including indirect ELISA, indirect blocking ELISA and agglutination tests. The percentage of serum samples positive for antibodies to a particular infection such as Edwardsiella tarda in agglutination test, indirect ELISA and indirect blocking ELISA as compared to indirect ELISA were 33.3, 83.6 and 66.6 % respectively. But the use of indirect ELISA was restricted due to the requirement of conjugates against several fish species. No significant difference (p0.05) in the mean optical density (O.D.) value found in indirect and competitive ELISA. Although the competitive ELISA was slightly less sensitive than the indirect ELISA it could accommodate a large number of serum samples and need of different anti-fish conjugates as required in Indirect ELISA was eliminated thereby proving the test a success in studying the pre-exposer of Indian major carps to pathogens in enzootic areas.