Institute for Experimental Pathology, University of Iceland, Keldur, Iceland.
Res Vet Sci. 2013 Feb;94(1):170-7. doi: 10.1016/j.rvsc.2012.07.011. Epub 2012 Aug 3.
The horse population in Iceland is a special breed, isolated from other equines for at least one thousand years. This provides an exceptional opportunity to investigate old and new pathogens in a genetically closed herd. Both types of equine gammaherpesviruses, EHV-2 and EHV-5, are common in Iceland. Genetic variation was examined by sequencing four genes, glycoprotein B (gB), glycoprotein H (gH), DNA polymerase and DNA terminase for 12 Icelandic and seven foreign EHV-2 strains. One Icelandic virus isolate, gEHV-Dv, induced syncytium formation, an uncharacteristic cytopathy for EHV-2 in equine kidney cells. When sequenced, the glycoprotein genes were different from both EHV-2 and EHV-5, but the polymerase and terminase genes had 98-99% identity to EHV-2. Therefore the gEHV-Dv strain can be considered a variant of EHV-2. Substantial genetic variability was seen within the EHV-2 glycoprotein genes but limited in the polymerase and terminase genes. The Icelandic EHV-2 strains do not seem to differ phylogenetically from the foreign viruses, despite isolation for over a thousand years.
冰岛的马种群是一个特殊的品种，与其他马科动物隔离了至少一千年。这为在一个遗传上封闭的畜群中研究旧的和新的病原体提供了一个极好的机会。两种马γ疱疹病毒，EHV-2 和 EHV-5，在冰岛都很常见。通过对 12 株冰岛和 7 株外国 EHV-2 毒株的四个基因（糖蛋白 B（gB）、糖蛋白 H（gH）、DNA 聚合酶和 DNA 末端酶）进行测序，研究了遗传变异。一种冰岛病毒分离株 gEHV-Dv，在马肾细胞中诱导合胞体形成，这是 EHV-2 的一种非典型细胞病变。当测序时，糖蛋白基因与 EHV-2 和 EHV-5 都不同，但聚合酶和末端酶基因与 EHV-2 的同一性为 98-99%。因此，gEHV-Dv 株可以被认为是 EHV-2 的一个变体。EHV-2 糖蛋白基因内存在大量遗传变异，但聚合酶和末端酶基因内的遗传变异有限。尽管已经隔离了一千多年，但冰岛的 EHV-2 株在系统发育上似乎与外国病毒没有区别。
