Characterization of a novel picornavirus isolated from moribund aquacultured clownfish

Elizabeth C. Scherbatskoy, Kuttichantran Subramaniam, Lowia Al-Hussinee, Kamonchai Imnoi, Patrick M. Thompson, Vsevolod L. Popov, Terry Fei Fan Ng, Karen L. Kelley, Rodolfo Alvarado, Jeffrey C. Wolf, Deborah B. Pouder, Roy P.E. Yanong, Thomas B. Waltzek

Research output: Contribution to journalArticle

Abstract

Over the last decade, a number of USA aquaculture facilities have experienced periodic mortality events of unknown aetiology in their clownfish (Amphiprion ocellaris). Clinical signs of affected individuals included lethargy, altered body coloration, reduced body condition, tachypnea, and abnormal positioning in the water column. Samples from outbreaks were processed for routine parasitological, bacteriological, and virological diagnostic testing, but no consistent parasitic or bacterial infections were observed. Histopathological evaluation revealed individual cell necrosis and mononuclear cell inflammation in the branchial cavity, pharynx, oesophagus and/or stomach of four examined clownfish, and large basophilic inclusions within the pharyngeal mucosal epithelium of one fish. Homogenates from pooled external and internal tissues from these outbreaks were inoculated onto striped snakehead (SSN-1) cells for virus isolation and cytopathic effects were observed, resulting in monolayer lysis in the initial inoculation and upon repassage. Transmission electron microscopy of infected SSN-1 cells revealed small round particles (mean diameter=20.0–21.7 nm) within the cytoplasm, consistent with the ultrastructure of a picornavirus. Full-genome sequencing of the purified virus revealed a novel picornavirus most closely related to the bluegill picornavirus and other members of the genus Limnipivirus. Additionally, pairwise protein alignments between the clownfish picornavirus (CFPV) and other known members of the genus Limnipivirus yielded results in accordance with the current International Committee on Taxonomy of Viruses criteria for members of the same genus. Thus, CFPV represents a proposed new limnipivirus species. Future experimental challenge studies are needed to determine the role of CFPV in disease.

Original languageEnglish (US)
Pages (from-to)735-745
Number of pages11
JournalJournal of General Virology
Volume101
Issue number7
DOIs
StatePublished - 2020

Keywords

  • Cell culture
  • Clownfish
  • Emerging disease
  • Molecular diagnostics
  • NGS
  • Ornamental aquaculture
  • PCR
  • Picornavirus
  • Viral discovery

ASJC Scopus subject areas

  • Virology

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  • Cite this

    Scherbatskoy, E. C., Subramaniam, K., Al-Hussinee, L., Imnoi, K., Thompson, P. M., Popov, V. L., Fan Ng, T. F., Kelley, K. L., Alvarado, R., Wolf, J. C., Pouder, D. B., Yanong, R. P. E., & Waltzek, T. B. (2020). Characterization of a novel picornavirus isolated from moribund aquacultured clownfish. Journal of General Virology, 101(7), 735-745. https://doi.org/10.1099/jgv.0.001421