Persistent development of adomavirus and aquareovirus in a novel cell line from marbled eel with petechial skin haemorrhage

Abstract

In Taiwan, a petechial haemorrhage disease associated with mortality has affected marbled eels (Anguilla marmorata). The eels were revealed to be infected with adomavirus (MEAdoV, previously recognized as a polyoma‐like virus). In this study, cell line DMEPF‐5 was established from the pectoral fin of a diseased eel. DMEPF‐5 was passaged >70 times and thoroughly proliferated in L‐15 medium containing 2%–15% foetal bovine serum at 20–30°C. Transcripts of neural cell adhesion molecule 1 and nestin genes, and nucleic acids of MEAdoV and a novel reovirus (MERV) in the cells were demonstrated by reverse transcription‐polymerase chain reaction analysis. Phylogenetic analysis revealed that the AdoV LO8 proteins mostly relate to adenovirus adenain, whereas MERV is close to American grass carp reovirus in Aquareovirus G, based on a partial VP2 nucleotide sequence. DMEPF‐5 cells are susceptible to additional viral infection. Taken together, the marbled eels with the haemorrhagic disease have coinfection with MEAdoV and MERV, and the pathogenic role of MEAdoV and MERV warrants research. DMEPF‐5 has gene expression associated with mesenchymal stem and progenitor cells and is the first cell line persistently infected with adomavirus and aquareovirus. DMEPF‐5 can facilitate studies of such viruses and haemorrhagic disease.

Isolation of a novel adomavirus from cultured American eels, Anguilla rostrata, with haemorrhagic gill necrosis disease

“…In contrast, natural VECNE also shows a reddening fins and a swollen abdomen (Inouye et al., 1994; Ono & Nagai, 1997), and the diseased marbled eels exhibit haemorrhaging throughout the body surface (Wen, 2017; Wen et al., 2016). It was suggested that MEAdoV is not the major factor causing the haemorrhaging and mortality in cultured marbled eels (Pao et al., 2019; Wen et al., 2016) and we had found that eel herpesvirus could cause haemorrhagic disease in cultured American eels (unpublished). Therefore, haemorrhaging might not be a typical sign caused by AEAdoV.…”

“…In this study, the discovery of a partial sequence of the S3H replicase (large T antigen-like) in AEAdoV and its high identity with MEAdoV (Figure 3c) indicated that it could be classified as a beta-adomavirus (Welch et al, 2020). to 22 kb (Pao et al, 2019). However, their sequences were highly divergent, including in biological function regions such as S3H replicase (Mizutani et al, 2011;Ono et al, 2007;Wen et al, 2016).…”

“…It was suggested that MEAdoV is not the major factor causing the haemorrhaging and mortality in cultured marbled eels (Pao et al, 2019;Wen et al, 2016) and we had found that eel herpesvirus could cause haemorrhagic disease in cultured American eels (unpublished). Therefore, haemorrhaging might not be a typical sign caused by AEAdoV.…”

Identification of virus infections of European eels intended for stocking measures

“…Knowledge about some virus infections of eels is still at the beginning and to date, some findings of eel viruses come from other eel species. For example, polyomavirus infections of Anguilla marmorata have been reported (Wen et al, 2016) and reovirus infections (Pao et al, 2019). Reovirus‐like particles have been isolated from European eels (Haenen et al, 2009) without further investigation.…”

Screening of Fish Cell Lines for Piscine Orthoreovirus-1 (PRV-1) Amplification: Identification of the Non-Supportive PRV-1 Invitrome

“…An example is the marbled eel cell line, DMEPF-5, and adomavirus. These cells retain adomavirus nucleic acid but do not appear to produce the virus [ 26 ].…”