Detection of koi herpesvirus (KHV) in healthy cyprinid seed stock

Abstract

Koi herpesvirus (KHV) disease is a lethal disease in common carp, an important food fish in Asian countries, the seed of which is used in restocking programs for freshwater fishery management. We inspected apparently healthy seed stock of common carp Cyprinus carpio L. and Siberian crucian carp Carassius auratus for the presence of KHV using PCR-based diagnostic tests as a part of a stock enhancement program from 2009 to 2010 in Korea. Consequently, KHV was detected from 24 of 232 inspections with yearly detection percentages of 5.2% in 2009 and 15.5% in 2010 using PCR primer sets for TK or SphI-5 as recommended by the OIE Manual of Diagnostic Tests for Aquatic Animals. Results indicate that the SphI-5 primer set was slightly more sensitive than the TK primer set, as shown by a higher detection rate. To determine the genotype of the KHV strains detected in this study, ORF40-specific PCR amplification was conducted, and the PCR products from 6 samples showed 100% nucleotide sequence identity with a Japanese strain (GenBank accession number AP008984) but not with US (DG657948) and Israeli strains (DG177346). This report conclusively demonstrated the presence of KHV in externally healthy seed of common carp and Siberian crucian carp, indicating a possible risk that subclinically infected seed stock can be released with a potential threat to wild populations. KEY WORDS: Carp · Cyprinus carpio · Carassius auratus · Cyprinid herpesvirus 3 · PCR · ORF40Resale or republication not permitted without written consent of the publisher Dis Aquat Org 112: [29][30][31][32][33][34][35][36] 2014 Marine and inland stock enhancement by releasing aquatic animals raised in hatcheries has been considered a potential management tool for increasing production and profitability of fisheries and meeting the demand for food requirements for an ever-increasing human population (Bartley et al. 2006). In Korea, hatchery-reared carp seed, especially common carp and Siberian crucian carp, have been released into the environment for the purpose of restoring the indigenous fish species and replenishing severely depleted fisheries in inland ranching programs.Concerns about unfavorable consequences of hatchery-reared seed releases such as the spread of pathogens, competition for food, and cannibalism, as well as genetic deterioration of wild stocks, have been increasing within the framework of aquatic animal health management (Fushimi 2001). Subasinghe (2005) also pointed out that movements of live aquatic animals and animal products (broodstock, seed, and feed) have accelerated the accidental spread and incursion of diseases into new populations and geographic regions, for example, through movements of hatchery-produced stocks. Thus special efforts have been required to prevent disease spread due to the release of cultured seed into the ecosystem, in terms of aquatic animal health management (Blankenship & Leber 1995).To prevent transmission of infectious agents by releasing hatchery-raised seed into the wider environment as part of...

Cyprinid Herpesvirus 3

“…In addition, CyHV-3 DNA, but no infectious particles, has been detected in several organs of fish after CyHV-3 infection . Finally, CyHV-3 DNA can be routinely detected in apparently healthy fish (Cho et al, 2014).…”

Susceptibility of Koi, Koi×Red Common Carp, and Red Common Carp×Koi to Koi Herpesvirus (KHV)

“…There is evidence of KHV in wild and farmed fish worldwide. In Asia, there are reports of this virus in fish cultured in Japan ( Sano et al, 2004 ), Taiwan ( Tu et al, 2004 ; Cheng et al, 2011 ), China ( Dong et al, 2011 ), Iran ( Rahmati-Holasoo et al, 2016 ), and Korea ( Gomez et al, 2011 ; Cho et al, 2014 ). KHV can be detected by a polymerase chain reaction (PCR) assay, an enzyme-linked immunosorbent assay (ELISA) or immunohistochemical (IHC) methods ( Akoi et al, 2011 ) in carp and koi ( Sano et al, 2005 ; Haramoto et al, 2009 ; Akoi et al, 2011 & Minamoto et al, 2012 ).…”