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Subject: Fisheries × Author: KUSHALA, K. B × End date: 2020 ×
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    ThesisItemOpen Access
    SCREENING OF FRESHWATER ORNAMENTAL FISHES FOR VIRAL DISEASES
    (KARNATAKA VETERINARY, ANIMAL & FISHERIES SCIENCES UNIVERSITY, BIDAR, 2019) KUSHALA, K. B; S.K.GIRISHA
    In the international ornamental fish trade, more than 90% of the freshwater fishes are farm bred and about 4000 species of freshwater ornamental fishes were traded every year. Hence, the global ornamental fish trade had become the platform for spread of exotic pathogens especially viral pathogens. Major DNA viruses viz., cyprinidae herpes virus-2, koi herpes virus (KHV), carp edema virus(CEV), epizootic haematopoietic necrosis virus (EHNV), infectious spleen and kidney necrosis virus (ISKNV), and RNA viruses viz., spring viraemia of carp virus (SVCV), viral haemorrhagic septicemia (VHS) and viral nervous necrosis virus(VNN) are causing diseases and results in significant economic loss in ornamental fish trade. Therefore, to develop a strategy to controls the diseases, the present study has been undertaken to screen the viral pathogens present in ornamental fishes traded in Karnataka. In this present study, moribund and dead ornamental fishes were collected from three districts viz., Dakshina Kannada, Bengaluru Central and Ramanagar. Totally 146 different ornamental fishes were screened for seven viral pathogens which were showing different clinical signs like haemorrhages, sunken yes, body discoloration, scale erosion and swelling gills. Out of 146 ornamental fish, ISKNV was detected in 20 samples (13.6%) and CEV was detected in 4 samples (2.37%) by PCR targeting specific genes but there was no co-infection of the both virus in a single fish. None of the samples were found to be positive for DNA viruses’ viz., KHV, EHNV and RNA viruses viz., SVCV, VHS and VNN. NCBI-BLAST analysis of sequenced CEV strains were more similar (97.4-99.94%) to the India and Germany CEV strains whereas ISKNV strains were more similar (98.76%- 100%) to ISKNV strains from Japan and Australia. Phylogenetic tree revealed that our CEV strains belong to lineage 1 of koi carp whereas our ISKNV strains belong to genotype I of Megalocytivirus. This is the first report of ISKNV and second report of CEV from India.