title: High genetic diversity of equine infectious anaemia virus strains from Slovenia revealed upon phylogenetic analysis of the p15 gag gene region.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  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.
  
  
  METHODS
  Cross-sectional study using material derived from post mortem examination.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: U
authors.initials: U
authors.lastname: Kuhar
authors.affiliation: Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: T
authors.initials: T
authors.lastname: Malovrh
mesh_terms: D000818:Animals; D004859:Equine Infectious Anemia / Q000453:epidemiology / Q000821:virology*; D015967:Gene Expression Regulation, Viral; D015683:Gene Products, gag / Q000235:genetics*; D014644:Genetic Variation; D006736:Horses; D004860:Infectious Anemia Virus, Equine / Q000235:genetics*; D010802:Phylogeny; D017524:Slovenia / Q000453:epidemiology
chemical_list: D015683:Gene Products, gag
keywords: equine infectious anaemia virus; gag gene region; horse; p15; phylogenetic analysis