Kuhar U, Malovrh T
Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia.
Equine Vet J. 2016 Mar;48(2):205-10. doi: 10.1111/evj.12404. Epub 2015 Feb 25.
The equine infectious anaemia virus (EIAV), which belongs to the Retroviridae family, infects equids almost worldwide. Every year, sporadic EIAV cases are detected in Slovenia.
To characterise the Slovenian EIAV strains in the p15 gag gene region phylogenetically in order to compare the Slovenian EIAV strains with EIAV strains from abroad, especially with the recently published European strains.
Cross-sectional study using material derived from post mortem examination.
In total, 29 EIAV serologically positive horses from 18 different farms were examined in this study. Primers were designed to amplify the p15 gag gene region. Amplicons of 28 PCRs were subjected to direct DNA sequencing and phylogenetic analysis.
Altogether, 28 EIAV sequences were obtained from 17 different farms and were distributed between 4 separate monophyletic groups and 9 branches upon phylogenetic analysis. Among EIAV strains from abroad, the closest relatives to Slovenian EIAV strains were European EIAV strains from Italy. Phylogenetic analysis also showed that some animals from distantly located farms were most probably infected with the same EIAV strains, as well as animals from the same farm and animals from farms located in the same geographical region.
This is the first report of such high genetic diversity of EIAV strains from one country. This led to speculation that there is a potential virus reservoir among the populations of riding horses, horses kept for pleasure and horses for meat production, with some farmers or horse-owners not following legislation, thus enabling the spread of infection with EIAV. The low sensitivity of the agar gel immunodiffusion test may also contribute to the spread of infection with EIAV, because some infected horses might have escaped detection. The results of the phylogenetic analysis also provide additional knowledge about the highly heterogeneous nature of the EIAV genome.
马传染性贫血病毒（EIAV）属于逆转录病毒科，几乎在全球范围内感染马科动物。每年，斯洛文尼亚都会检测到散发性EIAV病例。
对斯洛文尼亚EIAV毒株的p15 gag基因区域进行系统发育分析，以便将斯洛文尼亚EIAV毒株与国外的EIAV毒株进行比较，特别是与最近公布的欧洲毒株进行比较。
采用死后检查获得的材料进行横断面研究。
本研究共检查了来自18个不同农场的29匹EIAV血清学阳性马。设计引物扩增p15 gag基因区域。对28个PCR扩增产物进行直接DNA测序和系统发育分析。
总共从17个不同农场获得了28个EIAV序列，在系统发育分析中分布在4个独立的单系群和9个分支中。在国外的EIAV毒株中，与斯洛文尼亚EIAV毒株亲缘关系最近的是来自意大利的欧洲EIAV毒株。系统发育分析还表明，一些来自地理位置遥远农场的动物很可能感染了相同的EIAV毒株，同一农场的动物以及来自同一地理区域农场的动物也是如此。
这是关于一个国家EIAV毒株如此高遗传多样性的首次报告。这引发了一种推测，即役用马、休闲用马和肉用马群体中存在潜在的病毒库，一些农民或马主未遵守相关法规，从而导致EIAV感染传播。琼脂凝胶免疫扩散试验的低敏感性也可能导致EIAV感染传播，因为一些感染马可能未被检测到。系统发育分析结果也为EIAV基因组的高度异质性提供了更多知识。
