The Involvement of MGF505 Genes in the Long-Term Persistence of the African Swine Fever Virus in Gastropods

African swine fever virus (ASFV), a highly contagious and lethal virus affecting domestic and wild pigs, has raised global concerns due to its continued spread across Europe and Asia. While traditional transmission pathways involve suids and soft ticks, this study investigates the potential role of freshwater gastropods as environmental reservoirs capable of sustaining ASFV. We analysed ASFV survival in ten gastropod species after long-term co-incubation with the virus. Viral transcriptional activity, particularly of the late gene <i>B646L</i> and members of the multigene family <i>MGF505</i>, was evaluated in snail faeces up to nine weeks post-infection. Results revealed that several gastropods, including <i>Melanoides tuberculata</i>, <i>Tarebia granifera</i>, <i>Physa fontinalis</i>, and <i>Pomacea bridgesii</i>, support long-term persistence of ASFV, accompanied by increased <i>MGF505</i> gene expression. Notably, the simultaneous activation of <i>MGF5052R</i> and <i>MGF50511R</i> significantly correlated with higher <i>B646L</i> expression and extended viral survival, suggesting a functional role in ASFV maintenance. Conversely, antiviral (AV) activity assays showed that some gastropod faeces reduced replication of the unrelated Influenza virus, hinting at induced host defences. A negative correlation was observed between AV activity and the expression of <i>MGF505 2R/11R</i>, implying that ASFV may suppress antiviral responses to facilitate persistence. These findings suggest that certain gastropods may serve as overlooked environmental hosts, contributing to ASFV epidemiology via long term viral shedding. Further research is needed to clarify the mechanisms underlying ASFV-host interactions and to assess the ecological and epidemiological implications of gastropods in ASFV transmission cycles.