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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #404394
Research Project: Integrated Research to Improve Aquatic Animal Health in Warmwater Aquaculture

Location: Aquatic Animal Health Research

Title: Fish immune responses to natural infection with carp edema virus (Koi sleepy disease): An emerging fish pathogen

Author
item MULIYA SANKAPPA, NITHIN - Orise Fellow
item Abernathy, Jason

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/15/2023
Publication Date: 6/4/2023
Citation: Muliya Sankappa, N., Abernathy, J.W. 2023. Fish immune responses to natural infection with carp edema virus (Koi sleepy disease): An emerging fish pathogen [ABSTRACT]. 13th North American Comparative Immunology (NACI) Workshop, Auburn, AL. June 4-7, 2023.

Interpretive Summary:

Technical Abstract: The emerging pathogen carp edema virus (CEV) causes koi sleepy disease (KSD) in koi and common carp and can result in severe mortalities worldwide. In the present study, a total of 150 fish belonging to eight different families were sampled from ornamental fish retailers and farms in Karnataka, India. Following OIE protocols we confirmed CEV infection in 10 koi fish. CEV isolated was characterized by gene sequencing (partial 4a gene); results showed this strain had similarity with strains reported from other areas of India as well as Germany, with homology of 97.4–99.94% and belonging to genogroup IIa. TEM analysis of purified CEV, in vivo cohabitation, and tissue infection experiments further confirmed CEV. Viral load was significantly higher (10^6-7 copies) in koi collected from Dakshina Kannada than of Bengaluru (10^3-4 copies). Interestingly, other fish species belonging to the cyprinidae family were negative to CEV. To understand host–pathogen interaction, different organs including gill, kidney, liver, and spleen from koi naturally infected with CEV were used to study the immune gene responses via quantitative PCR. Eight innate and one adaptive immune response genes were analysed. Mortality was also examined in cohabitated and tissue infection experiments. Results indicated that TNF-a, RohTNF-a, iNOS, IFN-' and IL-10, and catalyze ß-2M of MHC class I pathway genes were upregulated in infected koi after 10 days post-infection. Significant differences were observed in mortalities between groups and the control. Results provide insights into the host responses and provide valuable information to devise intervention strategies to prevent and control disease due to CEV.