African swine fever virus alters soil microbial biomass and biodiversity: Evidence from experimental soil systems.

Background and Aim: African swine fever virus (ASFV) has expanded beyond its traditional ecological niches, raising concerns not only for animal health but also for environmental sustainability. While extensive research has focused on its persistence and transmission, little is known about its ecological effects in soil systems. This study aimed to investigate the influence of ASFV on soil microbial biomass, biodiversity, and associated ecological parameters. Materials and Methods: Eighteen anthrosol soil samples collected from agricultural regions of Armenia were subjected to controlled experimental conditions. Soil samples were treated with active ASFV (aASFV), inactivated ASFV (iASFV), and mock controls. Physicochemical properties, including pH and moisture content, were assessed. Microbial biomass was evaluated through soil protein quantification and viral nucleic acid (DNA and RNA) measurements. Microbial diversity was analyzed by enumerating culturable bacteria and fungi using selective media. Dissolved oxygen levels were measured to assess microbial activity. Quantitative real-time polymerase chain reaction was employed to evaluate viral genome dynamics and transcriptional activity. Statistical analyses were performed to determine correlations among measured variables. Results: ASFV exposure resulted in a general reduction in total microbial biomass, as evidenced by decreased soil protein content and viral nucleic acid concentrations in most samples. In contrast, microbial diversity, particularly among bacterial and fungal populations, showed an increasing trend, suggesting a restructuring of the microbial community. Active ASFV induced greater changes compared to the inactivated virus. A significant positive correlation was observed between protein content and microbial indicators, while a negative correlation was noted between oxygen levels and nucleic acid content. Viral transcriptional activity was detected in selected samples, with no evidence of complete viral replication. Limited detection of giant viruses suggested potential but inconclusive ecological interactions. Conclusion: ASFV alters soil ecosystems through complex, multidirectional effects, characterized by reduced biomass and increased microbial diversity. These findings indicate that ASFV may indirectly influence soil ecological processes, even in the absence of active replication. The study highlights the importance of incorporating environmental perspectives into ASFV research and provides a foundation for future investigations on virus-soil-microbiome interactions.