Ayanwale, A. | bioRxiv Science

bioRxiv2026

Small aberrant viral genomes induce the innate immune response to arenaviruses

Arenaviruses are a family of negative-sense RNA viruses mainly found in rodents in which they cause chronic asymptomatic infections. Some arenaviruses, however, can occasionally infect humans and cause pathogenic viral haemorrhagic fevers. These viral haemorrhagic fevers are associated with a massively dysregulated immune response characterized by excessive release of pro-inflammatory cytokines resulting in hyperinflammatory immunopathology. Here, we systematically characterize the immune response of human cells to a wide panel of mammalian arenaviruses and identify a clear distinction between New World viruses, which uniformly induce a robust interferon response, and Old World viruses, which do not induce any significant host response. This innate immune response is primarily driven by RIG-I-mediated RNA sensing and might be aided by differences in viral interferon antagonist expression patterns. Furthermore, we identified differences in quantity and type of non-standard viral genomes produced in unpassaged Old World and New World virus infections. Finally, we demonstrate that small non-standard viral RNA expression by New World viruses are key drivers of the innate immune response and might help explain how the host response can shape viral disease phenotypes and inform triage of patients.

microbiology↗

bioRxiv2025

Hantavirus stability and inactivation

Hantaviruses are zoonotic viruses that can cause highly pathogenic disease, including hantavirus cardiopulmonary syndrome (HCPS) and haemorrhagic fever with renal syndrome (HFRS), in humans with case-fatality rates of up to 50%. However, our understanding of the basic viral life cycle and the underlying causes of viral pathogenesis remains sparse, in large part due to a lack of molecular biology tools for hantaviruses and the need to work in high-containment laboratory facilities with these viruses. Here, we investigated the kinetics of infectious Tula virus (TULV) particle production in Vero E6 cells and subsequent stability in cell culture media. In addition, we evaluated the stability of infectious virus particles in response to different physical and environmental stresses, including heat, freezing, dehydration and UV exposure, answering key questions about the environmental transmission potential of hantaviruses. Interestingly, we observed a remarkable stability of TULV when stored at room temperature or colder, as well as after dehydration, which suggests that hantaviruses could remain infectious for a sustained period of time after being secreted by their host species. Subsequently, we determined the ability of commonly used virus inactivation methods, including RNA and protein extraction buffers, to inactivate TULV both in a cell-free and cell-associated context and found that TULV was efficiently inactivated by all these methods similar to other enveloped RNA viruses. Finally, we successfully validated the complete inactivation using these inactivation methods using the highly pathogenic HCPS-causing New World Andes virus (ANDV) and the HFRS-causing Old World Hantaan virus (HTNV). These results provide valuable information about safe and effective inactivation methods of viral samples and about the environmental risk potential of hantaviruses. Author summaryHantaviruses are ubiquitous rodent viruses and contain some of the most lethal known zoonotic viruses, including Andes virus (ANDV) and Hantaan virus (HTNV), with no FDA-or EMA-approved antiviral treatment or prevention options available. However, studying the molecular biology and pathogenesis of these viruses is significantly impeded by the need for biosafety level (BSL) 3 (or higher) containment facilities for most hantaviruses and a general lack of molecular biology tools. Our study provides a comprehensive analysis of the stability of infectious hantavirus particles in response to different physical and chemical stresses. We demonstrate that a diverse range of hantaviruses are effectively and quickly inactivated by commonly used generic viral inactivation methods. However, we also provide evidence for an inherent stability under environmental conditions that could enable prolonged transmission potential of hantaviruses, even after secretion from their host species. These data are essential information to design safe inactivation methods of infectious hantavirus material and offers insights into the environmental risks of hantavirus infections with implications for laboratory safety and public health measures.

microbiology↗