Grant Samantha A, Bienentreu Joe-Felix, Vilaça Sibelle Torres, Brunetti Craig R, Lesbarrères David, Murray Dennis L, Kyle Christopher J
Environmental and Life Sciences Graduate Program, Trent University, Peterborough, Ontario K9J 7B8, Canada.
Dis Aquat Organ. 2019 Apr 11;134(1):1-13. doi: 10.3354/dao03354.
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-2α. Few studies, however, have investigated the spatial distribution of FV3 variants at the population level3-data that can be used to further understand the spatial epidemiology of this disease. In this study, we sequenced the MCP and vIF-2α 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-2α, 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.
蛙病毒3（FV3）和FV3样蛙虹彩病毒可感染多种冷血水生物种，对全球两栖动物构成主要威胁。此前对FV3样病毒的研究主要通过保守的主要衣壳蛋白（MCP）部分以及推定的毒力基因vIF-2α来研究这些病原体的高级系统发育差异。然而，很少有研究在种群水平上调查FV3变体的空间分布——这些数据可用于进一步了解该疾病的空间流行病学。在本研究中，我们对从安大略省、艾伯塔省东北部和西北地区南部的加拿大水体中采集的127只FV3阳性两栖动物的MCP和vIF-2α进行了测序，以探索FV3内是否存在种内遗传变异。这些区域的两个标记缺乏变异，这表明加拿大缺乏FV3序列多样性，这可能暗示存在单一的感染源并已传播开来。然而，在艾伯塔省和西北地区的3个地点的样本中检测到一种未记录的变体，称为伍德布法罗蛙虹彩病毒（WBRV），它聚集在FV3样谱系中，MCP的序列同源性为99.3%。对于vIF-2α，除安大略省的6个样本外，所有序列均为预期的截短变体。后一组序列提示与普通产婆蟾病毒（CMTV）发生了重组。缺乏变异表明需要进行更高分辨率的基因组分析，以进一步探索该疾病的空间传播和种内变异。
