Dewals Benjamin, Thirion Muriel, Markine-Goriaynoff Nicolas, Gillet Laurent, de Fays Katalin, Minner Frédéric, Daix Virginie, Sharp Paul M, Vanderplasschen Alain
Immunology-Vaccinology (B43b), Department of Infectious and Parasitic Diseases, Faculty of Veterinary Medicine, University of Liège, B-4000 Liège, Belgium.
Institute of Genetics, University of Nottingham, Queens Medical Centre, Nottingham NG7 2UH, UK.
J Gen Virol. 2006 Jun;87(Pt 6):1509-1519. doi: 10.1099/vir.0.81757-0.
Bovine herpesvirus 4 (BoHV-4) has been isolated from cattle throughout the world, but virological and serological studies have suggested that the African buffalo is also a natural host for this virus. It has previously been found that the Bo17 gene of BoHV-4 was acquired from an ancestor of the African buffalo, probably around 1.5 million years ago. Analysis of the variation of the Bo17 gene sequence among BoHV-4 strains suggested a relatively ancient transmission of BoHV-4 from the buffalo to the Bos primigenius lineage, followed by a host-dependent split between zebu and taurine BoHV-4 strains. In the present study, the evolutionary history of BoHV-4 was investigated by analysis of five gene sequences from each of nine strains representative of the viral species: three isolated from African buffalo in Kenya and six from cattle from Europe, North America and India. No two gene sequences had the same evolutionary tree, indicating that recombination has occurred between divergent lineages; six recombination events were delineated for these sequences. Nevertheless, exchange has been infrequent enough that a clonal evolutionary history of the strains could be discerned, upon which the recombination events were superimposed. The dates of divergence among BoHV-4 lineages were estimated from synonymous nucleotide-substitution rates. The inferred evolutionary history suggests that African buffalo were the original natural reservoir of BoHV-4 and that there have been at least three independent transmissions from buffalo to cattle, probably via intermediate hosts and--at least in the case of North American strains--within the last 500 years.
牛疱疹病毒4型（BoHV - 4）已在世界各地的牛群中分离得到，但病毒学和血清学研究表明，非洲水牛也是该病毒的天然宿主。此前已发现，BoHV - 4的Bo17基因是从非洲水牛的一个祖先那里获得的，时间可能在大约150万年前。对BoHV - 4毒株中Bo17基因序列变异的分析表明，BoHV - 4从水牛向原牛谱系的传播相对古老，随后在瘤牛和普通牛的BoHV - 4毒株之间出现了宿主依赖性分化。在本研究中，通过分析代表该病毒种的9个毒株中每个毒株的5个基因序列，对BoHV - 4的进化历史进行了研究：3个毒株从肯尼亚的非洲水牛中分离得到，6个毒株从欧洲、北美和印度的牛中分离得到。没有两个基因序列具有相同的进化树，这表明在不同谱系之间发生了重组；为这些序列确定了6次重组事件。然而，基因交换发生的频率足够低，以至于可以识别出毒株的克隆进化历史，并在此基础上叠加重组事件。根据同义核苷酸替换率估计了BoHV - 4谱系之间的分化日期。推断出的进化历史表明，非洲水牛是BoHV - 4的原始天然宿主，并且至少有三次从水牛到牛的独立传播，可能是通过中间宿主，而且至少就北美毒株而言，这种传播发生在过去500年内。
