Low intraspecific variation of Frog virus 3 with evidence for novel FV3-like isolates in central and northwestern Canada

• Published in: Diseases of Aquatic Organisms
• Main Authors: Grant SA, Bienentreu JF, TORRES VILACA S, Brunetti CR, Lesbarreres D, Murray DL, Kyle CJ
• Other Authors: Grant, Sa, Bienentreu, Jf, TORRES VILACA, S, Brunetti, Cr, Lesbarreres, D, Murray, Dl, Kyle, Cj
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2019
• Subjects: Frog virus 3; Ranavirus; Phylogenetic; Major capsid protein; vIF-2α; Amphibians; Wildlife disease; Northwest Territories; Canada; Wood Buffalo
• Online Access: https://hdl.handle.net/11392/2502492; https://doi.org/10.3354/dao03354; https://www.int-res.com/abstracts/dao/v134/n1/p1-13/

Frog virus 3 (FV3) and FV3-like ranaviruses can infect a variety of cold-blooded aquatic species and present a primary threat to amphibians across the globe. Previous studies of FV3-like viruses have largely investigated higher-level phylogenetic distinctions of these pathogens via portions of the conserved major capsid protein (MCP), and the putative virulence gene vIF-2 alpha. Few studies, however, have investigated the spatial distribution of FV3 variants at the population level-data that can be used to further understand the spatial epidemiology of this disease. In this study, we sequenced the MCP and vIF-2 alpha of 127 FV3-positive amphibians sampled from Canadian water bodies in Ontario, northeastern Alberta, and southern Northwest Territories to explore whether intraspecific genetic variation exists within FV3. There was a lack of variation at the 2 markers across these regions, suggesting that there is a lack of FV3 sequence diversity in Canada, which may hint at a single source of infection that has spread. However, an undocumented variant termed Wood Buffalo ranavirus (WBRV) was detected in samples from 3 sites in Alberta and Northwest Territories that clustered within the FV3-like lineage with 99.3% sequence homology for MCP. For vIF-2 alpha, all sequences were the expected truncated variant except for 6 samples in Ontario. These latter sequences were suggestive of recombination with common midwife toad virus (CMTV). The lack of variation suggests that higher-resolution genome analyses will be required to further explore the spatial spread and intraspecific variation of the disease.