Isolation of a bohle-like iridovirus from boreal toads housed within a cosmopolitan aquarium collection

Kwang Cheng, James K. Jancovich, Jennifer Burchell, Mark D. Schrenzel, Drury R. Reavill, Denise Imai, Maryanne Kirkendall, Leslie Woods, Allan P. Pessier

Research output: Chapter in Book/Report/Conference proceedingChapter

18 Scopus citations


A captive 'survival assurance' population of 56 endangered boreal toads Anaxvrus boreas boreas, housed within a cosmopolitan collection of amphibians originating from Southeast Asia and other locations, experienced high mortality (91%) in April to July 2010. Histological examination demonstrated lesions consistent with ranaviral disease, including multicentric necrosis of skin, kidney, liver, spleen, and hematopoietic tissue, vasculitis, and myriad basophilic intracytoplasmic inclusion bodies. Initial confirmation of ranavirus infection was made by Taqman real-time PCR analysis of a portion of the major capsid protein (MCP) gene and detection of iridovirus-like particles by transmission electron, microscopy. Preliminary DNA sequence analysis of the MCP, DNA polymerase, and neurofilament protein (NFP) genes demonstrated highest identity with Bohle iridovirus (BIV). A virus, tentatively designated zoo ranavirus (ZRV), was subsequently isolated, and viral protein profiles, restriction fragment length polymorphism analysis, and next generation DNA sequencing were performed. Comparison of a concatenated set of 4 ZRV genes, for which BIV sequence data are available, with sequence data from representative ranaviruses confirmed that ZRV was most similar to BIV. This is the first report of a BIV-like agent outside of Australia. However, it is not clear whether ZRV is a novel North American variant of BIV or whether it was acquired by exposure to amphibians co-inhabiting the same facility and originating from different geographic locations. Lastly, several surviving toads remained PCR-positive 10 wk after the conclusion of the outbreak. This finding has implications for the management of amphibians destined for use in reintroduction programs, as their release may inadvertently lead to viral dissemination.

Original languageEnglish (US)
Title of host publicationDiseases of Aquatic Organisms
Number of pages14
StatePublished - Sep 30 2014
Externally publishedYes


  • Bohle iridovirus
  • Boreal toads
  • Ranavirus
  • Survival assurance colonies
  • Viral taxonomy

ASJC Scopus subject areas

  • Aquatic Science
  • Ecology, Evolution, Behavior and Systematics
  • Medicine(all)


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