Genetic clustering of Borna disease virus natural animal isolates, laboratory and vaccine strains strongly reflects their regional geographical origin.

The research investigates the genetic evolution and variability of the Borna disease virus (BDV) and finds that its genetic clustering strongly matches the geographical regions from which the samples were originially collected.

Objective of the Research

The study intends to provide a more detailed understanding into the genetic evolution and variability of Borna disease virus (BDV). The researchers used phylogenetic analyses to understand the genetic diversity and geographical relationship among various BDV strains including field viruses from naturally infected animals, across different regions, BDV vaccine strain ‘Dessau’, and four laboratory strains.

Methodology

• Analyzing four regions of the BDV genome: the complete p40, p10 and p24 genes and the 5′-untranslated region of the X/P transcript.
• The degree of genetic identity between BDV isolates was examined, not considering factors such as host species and year of isolation.

Findings

• The researchers discovered that BDV isolates from the same geographical region had a higher degree of genetic identity with each other than those from different regions.
• Five genetic clusters were identified within the endemic areas which coincided with the geographical regions the viruses came from.
• Some mixed groups were found that consisted of samples from different areas, mainly from the federal states of Thuringia and Lower Saxony in Germany. However, these groups still demonstrated a geographical clustering pattern.
• The BDV vaccine strain ‘Dessau’, and the laboratory strains also included in the study also aligned with these identified genetic clusters based on their geographical origins.
• All field and lab strains, including the vaccine strain, were distinctly separated from the latest BDV strain No/98, which was highly divergent and originated from a non-endemic area in Austria.

Conclusion

The study concludes that the genetic diversity of the Borna disease virus vividly mirrors its geographical origin, both for natural and laboratory strains. This information could be utilized to trace the origin of BDV strains, as well as to understand how the virus has spread and evolved over time.