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Initially they are flat, firm, smooth and translucent, but they soon grow thicker, giving the impression of paraffin drops on the skin. It can infect other cyprinids such as Crucian carp and grass carp but is rarely fatal, even in the young of these species. 2005, Eide et al. De ziekte komt dan later tot uiting zodra de voor het virus ideale watertemperatuur is bereikt. However, envelope glycoprotein gene regions targeted in this study showed polymorphisms, indicating that the Korean CyHV-3 isolate was genetically different from those of the USA, Israel, and Japan isolates. Bergmann (Friedrich Loeffler Institute, Germany), and koi fin cells were prepared as previously described by Ronen et al. Indeed, in such a case, a higher number of viral proteins would be expected, in particular the most abundant ones [ 31 ].

The cells were cultured at 26°C in 5% (vol/vol) CO2 using a growth medium (GM) consisting of Leibovitz’s L-15 medium, 2% (vol/vol) fetal bovine serum, 0.075% (wt/vol) NaHCO3, 2 mM l-glutamine, 0.012% (wt/vol) kanamycin, and 270 U/ml penicillin G. In the case of Kaposi’s sarcoma herpesvirus (KSHV), the major latency antigen (LANA [latency-associated nuclear antigen]) (28) is expressed from the direct repeat region 7 (DR7). 1985a), and was described with the dimensions of 113 and 190 nm for the nucleocapsid and mature enveloped virion respectively (Sano et al. Spleen were treated for quantification of carp gene expression by RT-qPCR (see Figure 11). After being frozen-thawed twice, the homogenate was centrifuged at 4,500 ×g for 30 min at 4°C (Sigma 3K15). Furthermore, we studied the effect of cyhv3Il10 on cells of the innate as well as adaptive branches of the immune system of carp. Two days after seeding CCB cells into fresh 24-well plates, a 100 μl aliquot of CyHV-3 at 103.39 TCID50/ml was added to each plate and incubated at 22 °C.

Among the components of the innate immune system, the mucus covering the external and internal surfaces of the fish is thought to play a key role in the inhibition of pathogen entry into the host [8],[11]. These results suggest that CNGV(KHV) and the other CyHVs are members of a unique viral group, and CNGV(KHV) was thus designated CyHV-3 [9]. Dissected fishes and isolated organs were analysed for ex vivo bioluminescence. These observations then raise a key question: is the transmissibility of CyHV-3 optimized by the evolution of low virulence strains of virus that induce latency in fish? Also, ORFs encoding a dozen virion proteins have been identified by mass spectrometry (5), and an additional ORF encodes a mucin-like glycoprotein (29). To avoid removal of skin mucus, fish were caught using a container rather than a fish net, and they were manipulated with great care wearing humidified latex gloves. First, the KHV genome sequence has been published only recently (1).

Because viruses are obligate parasites, a particularly important question is how the viruses transmit between hosts to perpetuate the infection in host populations. In Lake Biwa in Japan, 60 to 80% of the wild carp population (>100,000) died in 2004, presumably due to CyHV-3 infection (Shiga Prefectural Government, http://www.pref.shiga.jp/g/suisan-s/seika/files/seikah1711.pdf [in Japanese]) (18). In aquaculture, LAMP assays have been developed to detect fish and shellfish pathogens including aquatic DNA viruses such as red seabream iridovirus (RSIV) [9], white spot syndrome virus (WSSV) [10–14], koi herpesvirus (KHV, CyHV-3) [15–19], infectious hypodermal and hematopoietic necrosis virus (IHHNV) [20–22], hepatopancreatic parvovirus (PmDNV) [23], Singapore grouper iridovirus (SGIV) [24], acute viral necrobiotic virus (AVNV) [25], turbot reddish body iridovirus (TRBIV) [26], infectious spleen and kidney necrosis virus (ISKNV) [27], lymphocystis disease virus (LCDV) [28], ostreid herpesvirus 1 (OsHV-1) [29], and soft shelled turtle iridovirus (STIV) [30]. Thus, the disease is a great threat not only to the cultivation industry and koi collectors but also to the natural carp population. Our results revealed that the life cycle of CyHV-3 may fit perfectly into the ecology of its host, resulting in the long-term persistence of this emerging virus in wild common carp populations. These observations suggest KHV virions mature through a complex morphological pathway including two distinct envelopments, which have been found only in herpesviruses. The PCR assay generates a 141 bp amplicon and reliably detects down to 10 copies of control plasmid DNA sequence (analytic sensitivity).

Infectious CyHV-3 was produced stably in CCF-K104 cells over 30 viral passages. In this study, the analytical and diagnostic performance of an alternative serum neutralization (SN) method based on the detection of CyHV-3-specific antibodies was assessed using 151 serum or plasma samples from healthy and naturally or experimentally CyHV-3-infected carp. Safety and efficacy are critical factors in assessing the suitability of biocontrol agents, and extensive host-specificity testing suggests that CyHV-3 is safe. This study aimed to determine the genetic basis underlying the common carp immune response to the CyHV-3 virus. There is evidence that CyHV-3 was actually present in carp in the UK in 1996 (Aoki et al, 2007).