First outbreak of an infection with infectious spleen and kidney necrosis virus (ISKNV) in ornamental fish in Germany

Abstract

In 2014, infectious spleen and kidney necrosis virus (ISKNV), a member of the genus Megalocytivirus, was detected for the first time in ornamental fish in Germany. Since 2013, angelfish Pterophyllum spp. originating from Colombia have experienced significant epizootics in a number of German retailers' facilities. The diseased fish showed symptoms such as increased ventilation, swollen gills, and ulcerations of the skin. In 2014, diseased angelfish P. altum and platys Xiphophorus maculatus maintained in the same recirculating system were examined. Histopathological lesions included hypertrophic cells, single-cell necrosis, and an inflammatory infiltration of granulocytes, lymphocytes, and macrophages in liver, spleen, and kidney. Transmission electron microscopy revealed the presence of numerous poly gonal viral particles (150 nm in diameter) within the cytoplasm of enlarged cells. A PCR assay for the detection of megalocytiviruses amplified 777 bp of major capsid protein gene that was 100% identical to ISKNV. This is the first report of an ISKNV outbreak in Germany that most probably was introduced by infected angelfish from Colombia. To our knowledge, this is the first report of ISKNV detected in fish imported from South America. Given the lethal nature of megalocytiviruses, proper biosecurity would seem prudent in countries like Germany where these emerging pathogens are not established.

Detection of infectious spleen and kidney necrosis virus (ISKNV) and turbot reddish body iridovirus (TRBIV) from archival ornamental fish samples

“…Without further analysis of samples, it remains unclear whether a megalocytivirus was involved. Similarly, a recent study detected ISKNV in association with altum angelfish P. altum recently imported from Colombia, although it is unclear in that instance whether the megalocytivirus originated from Colombia, or was introduced there from Asia (Jung-Schroers et al 2016).…”

First description of a natural infection with spleen and kidney necrosis virus in zebrafish

“…In Europe, ISKNV was recently reported in Germany affecting Pterophyllum sp. and Xiphophorus maculatus , and probably introduced by infected angelfish from Colombia (Jung‐Schroers et al., ). The international trade of fish for food and ornamental aquaculture has facilitated the spread of these viruses to distant regions.…”

“…In a histopathological manner, hypertrophic cells with large basophilic cytoplasmic inclusions can be found in internal organs (Gibson‐Kueh et al., ; He et al., ). Outbreaks have occurred most frequently in East and South‐East Asia (Subramaniam, Shariff, Omar, & Hair‐Bejo, ), although the international trade of ornamental fish has aided the spread of these viruses to Europe (Jung‐Schroers et al., ; Sriwanayos et al., ) and Australia (Mohr et al., ; Nolan, Stephens, Crockford, Jones, & Snow, ; Rimmer, Whittington, Tweedie, & Becker, ; Rimmer et al., ).…”

CyHV‐2 transmission in traded goldfish stocks in Germany—A case study

“…Because a viral aetiology was in suspicion, two end‐point PCRs were used: (1) a pan‐alloherpesviral PCR (Waltzek et al., ) and (2) megalocytiviruses PCR including infectious spleen and kidney necrosis virus (Kurita & Nakajima, ). Both PCRs were performed as described earlier (Jung‐Schroers et al., ). These were followed by two PCR protocols for the detection of CyHV‐2, an end‐point PCR targeting a fragment of the viral DNA helicase (Waltzek, Kurobe, Goodwin, & Hedrick, ) and a SYBR Green quantitative PCR (Wang et al., ).…”