Toscana virus (TOSV) is a reemerging sandfly-borne enveloped virus causing neuro-invasive infections in humans. Although endemic in the Mediterranean basin, diagnostics, therapeutics, and research on TOSV have been neglected. Our results highlight the crucial role of late endosomal maturation in TOSV entry into both fixed and live human neurons and cell lines, shedding light on atypical viral fusion mechanisms. Notably, the fusion process of TOSV appears, at least in part, reversible, and the virus depends on progressive acidification in endosomes for activation and penetration, rather than a specific pH threshold. The information gained here lays the basis for future research into entry inhibitors against not only TOSV, but all viruses using similar penetration strategies.

Read all about the results in the article published in the journal PLoS Pathogens (August 24, 2023)