Chapter 14 - Biotechnological tools in diagnosis and control of emerging fish and shellfish diseases

Abstract

Aquaculture is the fastest growing animal food-producing sector, growing at nearly a rate of 7% annually. However, rapid aquaculture growth has been accompanied by increased incidences of occurrence of infectious diseases, causing severe economic loss to the farming community. Aquaculture needs innovative biotechnological interventions to overcome challenges in terms of rapid disease diagnosis, production of disease-free or high health broodstock for seed production, suitable preventive and therapeutic measures to control disease outbreaks. During the last few years, molecular techniques have been increasingly employed to diagnose fish disease. These techniques are potentially faster and more sensitive than traditional culture, serology, and histology methods. DNA-based techniques like polymerase chain reaction (PCR), real-time-PCR (qPCR), multiplex PCR, DNA probe-based in situ hybridization, and microarray, etc. have a wide scope of application in fish disease diagnosis. Again, pulsed-field gel electrophoresis, amplified fragment length polymorphism, ribotyping, repetitive element sequence-based PCR, enterobacterial repetitive intergenic consensus-polymerase chain reaction, and multilocus sequence typing -based genomic fingerprinting methods, combined with computer-assisted pattern analysis have been useful in typing and characterization of fish pathogens. qPCR assays are also helpful to determine the presence of specific genes and alleles, typing of strains and isolates, antimicrobial resistance profiling, and toxin production. As in other animal sectors, probiotic and bioremediation products have scope of application in aquaculture for disease and environmental management and are being used in fish and shrimp farming to control disease outbreaks and upkeep of culture environment. There is an urgent need for development of suitable prophylactic measures in terms of single or multivalent vaccines, DNA vaccines, immunostimulants, organic products, nanotechnology-based products, etc. to control disease outbreaks. These biotechnological tools can be used as a routine tool for rapid diagnosis of fish pathogens in filed diagnosis besides their use in epidemiological studies of infectious fish diseases.