High genetic diversity of equine infectious anaemia virus strains from Slovenia revealed upon phylogenetic analysis of the p15 gag gene region.

This research article investigates the various strains of the equine infectious anaemia virus (EIAV) within Slovenia, providing insight into their genetic diversity and phylogenetic relationships. Notably, there is a surprisingly high genetic diversity of EIAV strains within the country, indicating potential influences such as relaxed legislation or low detection rates.

Research Objective

• The primary objective of this research was to characterize Slovenian strains of the equine infectious anaemia virus (EIAV) using phylogenetic analysis, focusing primarily on the p15 gag gene region. This would allow for comparison between these strains and others from different regions, with particular attention given to comparing Slovenian strains with those recently identified in Europe.

Methods Used

• This cross-sectional study analyzed material collected during post mortem examinations from 29 serologically positive horses across 18 different farms in Slovenia.
• The methodological approach involved the design and implementation of primers to amplify the p15 gag gene region in EIAV strains. The resulting amplicons from 28 of these PCR cycles were then subjected to direct DNA sequencing and phylogenetic analysis.

Results Acquired

• A total of 28 EIAV sequences were obtained and these corresponded to 17 different farms. Phylogenetically, these sequences split into four monophyletic groups and spanned nine branches.
• It was established that the closest relatives to the Slovenian EIAV strains were strains identified in Italy.
• The analysis also revealed that some animals from geographically distant farms were likely infected with the same strains of EIAV. The same was true for animals living on the same farm or within the same geographical area.

Conclusion

• This research represents the first report demonstrating such a high level of genetic diversity among EIAV strains in a single country – Slovenia in this case.
• This raised the possibility that there may be a virus reservoir among populations of riding horses, horses kept for pleasure and horses for meat production. A lack of adherence to legislation by certain farmers or horse-owners may also be responsible for the spread of EIAV.
• The low sensitivity of the agar gel immunodiffusion test might be another factor contributing to the spread of EIAV, as some infected horses could go undetected.
• The results bring new insight into the heterogeneous nature of the EIAV genome, thereby contributing to the broader understanding of this virus.