Infections of nervous necrosis virus in wild and cage‐reared marine fish from South China Sea with unexpected wide host ranges

Abstract

The concerns about the impact of the nervous necrosis virus (NNV) infections in wild fish have been raised. This paper presents the results of quarterly surveys of NNV in wild and cage-reared marine fish from South China Sea. Samples of 892 wild fish belonging to 69 species and 381 cage-reared fish belonging to 11 species were collected and were detected by seminested PCR and nested PCR. In the case of seminested PCR, the positive signal was detected in 3.0% and 3.1% samples of wild and cage-reared fish, respectively. However, by nested RT-PCR, the positive signal was observed in 42.3% and 63.0% samples of wild and cage-reared fish, respectively. If the fish species were considered, the positive signal was detected in 21.7% and 72.7% species of wild and cage-reared fish by seminested PCR assay, respectively. However, by nested RT-PCR, the positive signal was observed in 65.2% and 100% species of wild and cage-reared fish, respectively. The nucleotide sequences of the nested PCR products were determined. Phylogenetic tree showed that all the obtained viral isolates belonged to the red-spotted grouper nervous necrosis virus (RGNNV) genotype. Thirty-five species of the marine fish were the new hosts of NNV.

Betanodavirus and VER Disease: A 30-year Research Review

“…In recent The RGNNV genotype, which affects tropical and temperate fish species, is the most widely distributed ( Figure 2) and has the highest number of susceptible species (Tables 1, 2 and 4). In recent years, surveys conducted in different geographical areas have shown that RGNNV is widely distributed Pathogens 2020, 9, 106 6 of 46 not only in farmed but also among wild fish in the Mediterranean basin and along the coasts of Asia and Australia [46,[62][63][64][65][66][67][68][69][70][71][72]. It has also been isolated from farmed white seabass (Atractoscion nobilis) in California [73].…”

“…It is well documented that changes experienced by ecosystems will affect the epidemiology of infectious diseases in animals, in the wild and under intensive farming conditions, including aquaculture [152][153][154][155][156]. The high number of wild asymptomatic species infected with NNV, mainly in Asian and Mediterranean countries [62,64,[66][67][68]71,80,82] and the quick rise in the viral load and subsequent outbreak of mortalities observed in experimentally infected sole when water temperature increased from 16 to 22 • C [148], suggest that VER outbreaks could have dramatic effects on natural populations, as has already been reported for some endangered fish species in the Mediterranean [72,96,109]. On the other hand, it could be argued that ocean warming could decrease the pathologies associated with the BFNNV genotype.…”

Characterization and viral susceptibility of a brain cell line from brown‐marbled grouper Epinephelus fuscoguttatus (Forsskål) with persistent betanodavirus infection

“…; Liu et al . ). Following RGNNV infection, the interferon‐induced myxovirus resistance (Mx) proteins are upregulated in grouper cells (Chen et al .…”

“…Redspotted grouper nervous necrosis virus (RGNNV) is the main betanodavirus species that infect groupers (Chi et al 1997;Lai et al 2001;Tanaka et al 2003). RGNNV, which causes mass mortality (80-100%) in larvae and juveniles, has been a serious problem for farmed and wild groupers since 1994 (Chi et al 1997;Lai et al 2001;Gomez et al 2009;Bandin & Dopazo 2011;Vendramin et al 2013;Kara et al 2014;Liu et al 2015). Following RGNNV infection, the interferon-induced myxovirus resistance (Mx) proteins are upregulated in grouper cells (Chen et al 2006), and these proteins can inhibit viral propagation (Chen et al 2006;Lin et al 2006;Fern andez-Trujillo et al 2013;Wu, Kai & Chi 2013) by interacting with viral RNA-dependent RNA polymerase (RdRp) and coat protein (Chen et al 2008;Wu, Lu & Chi 2010).…”

Detection and molecular characterization of betanodaviruses retrieved from bivalve molluscs

“…Viral encephalopathy and retinopathy is mainly observed in farmed fish, although severe outbreaks were reported in wild fish, mainly groupers (Gomez et al., ; Vendramin et al., ). Furthermore, asymptomatic betanodavirus infection has also been detected in wild fish (Baeck et al., ; Barker et al., ; Ciulli, Galletti, Grodzki, Alessi, Battilani, & Prosperi, ; Gomez, Baeck, Kim, Choresca, & Park, ; Gomez et al., ; Liu et al., ; Panzarin et al., ). The occasional presence of betanodaviruses in invertebrates was detected in the Mediterranean Sea, South Korea and Japan (Ciulli, Grodzki, Bignami, Serratore, & Prosperi, ; Fichi et al., ; Gomez, Baeck, Kim, Choresca, & Park, ; Gomez, Mori, Okinaka, Nakai, & Park, ; Gomez et al., ; Panzarin et al., ).…”