Carp edema virus‐related mortality in wild adult common carp (cyprinus carpio) in Italy

Abstract

Mortality in wild fish populations represents a challenging issue for public fish health inspectors. When a single fish species is involved, an infective aetiology is frequently suspected, with focus on viral notifiable diseases. However, other viral agents not subjected to regulation and causing mortality in common carp have been reported such as carp edema virus (CEV). In mid‐June 2020, a severe common carp mortality was observed in an artificial lake in north‐east of Italy. Sleepy fish were noted some days before the beginning of the mortality itself, which lasted several days and involved over 340 adult specimens. During the outbreak, water temperature was around 15°C, water quality was normal, and no adverse meteorological events were reported in the area. Four specimens, which showed severe cutaneous hyperaemia and increased mucus production on skin and gills, were tested by bacteriological methods and virological analysis targeting the main carp pathogens. Molecular analysis performed on gills, kidney and brains from all the fish analysed resulted positive for CEV, which, based on anamnestic information and laboratory findings, was considered the responsible for the mortality event herein described.

Clinical and Laboratory Parameters of Carp Edema Virus Disease: A Case Report

“…Although the gills are the main target organ of CEV [ 36 ], other organs (heart, kidney, skin, intestine, and pancreatic tissue) also showed histopathological changes. Microscopic changes on internal organs of CEV-affected fish were described by several authors, more commonly in koi [ 6 , 11 , 38 ] than in common carp [ 39 ]. Previous studies described kidney swelling, degeneration, and necrosis of tubular epithelial cells, inflammatory infiltration of renal interstitium [ 6 , 11 ], congestion of renal interstitium [ 39 ], necrotic lesions in spleen and hepatopancreas, myocarditis, and diffuse enteritis [ 11 ].…”

A natural outbreak of infectious spleen and kidney necrosis virus threatens wild pearlspot, Etroplus suratensis in Peechi Dam in the Western Ghats biodiversity hotspot, India

“…The Peechi dam comes under the premises of Peechi‐Vazhani wildlife sanctuary in the Western Ghats., which is considered as one of the regions harbouring the richest biodiversity in the world. Recently, virus‐associated mortality events were reported for CEV in wild carps from natural and artificial lakes in the United States and Italy, respectively (Marsella et al., 2021; Tolo et al., 2021). A fish viral disease outbreak in this sensitive region may therefore lead to irreversible biodiversity losses among the endemic wild fish population.…”

It is everywhere—A survey on the presence of carp edema virus in carp populations in Germany

“…CEV was initially reported as originating from various populations of ornamental koi in Japan (Ono et al., 1986; Oyamatsu et al., 1997) in the USA (Hedrick et al., 1997) and in several European countries (Way et al., 2017). Recently, however, this virus was identified in populations of farmed common carp in China, the main producer of common carp globally (Luo et al., 2020; Zhang et al., 2017), and in several major European producers like Poland (Matras et al., 2017), Hungary (Adamek, Baska, et al., 2018), the Czech Republic and Slovakia (Matějíčková et al., 2020), Serbia (Radosavljevic et al., 2018), Italy (Marsella et al., 2021), Croatia (Zrnčić et al., 2020) and Germany (Bachmann & Keilholz, 2016). Except for Japan, where the presence of CEV has been more intensively studied on farms from several regions of the country (Oyamatsu et al., 1997), the other reports describe disease outbreaks in a single population or in a limited number of populations, and do not include an estimation of the spread and the impact of the infection on carp farming or the koi trade.…”

“…CEV was initially reported as originating from various populations of ornamental koi in Japan (Ono et al, 1986;Oyamatsu et al, 1997) in the USA (Hedrick et al, 1997) and in several European countries (Way et al, 2017). Recently, however, this virus was identified in populations of farmed common carp in China, the main producer of common carp globally (Luo et al, 2020;Zhang et al, 2017), and in several major European producers like Poland (Matras et al, 2017), Hungary (Adamek, Baska, et al, 2018), the Czech Republic and Slovakia (Mat ějíčková et al, 2020), Serbia (Radosavljevic et al, 2018), Italy (Marsella et al, 2021), Croatia (Zrnčić et al, 2020) and Germany (Bachmann & Keilholz, 2016).…”

“…KSD caused by infection with CEV was initially detected in koi populations in Japan in the 1970s (Murakami et al., 1976). Since then, the virus has been found in ornamental koi and carp in North America (Hedrick et al., 1997; Lovy et al., 2018), in many European countries including the UK (Way & Stone, 2013), the Netherlands and France (Haenen et al., 2016; Haenen et al., 2014), Austria (Lewisch et al., 2015), Germany (Jung‐Schroers et al., 2015), Poland (Matras et al., 2017), Hungary (Adamek et al., 2018), the Czech Republic and Slovakia (Matějíčková et al., 2020), Serbia (Radosavljevic et al., 2018), Italy (Marsella et al., 2021) and Croatia (Zrnčić et al., 2020) as well as in Asia besides Japan and China (Luo et al., 2020; Zhang et al., 2017), India (Swaminathan et al., 2016) and Thailand (Pikulkaew et al., 2020). Although the virus appears to be present in European koi and carp populations, its prevalence and virulence are not well studied.…”