Characterization of emerging Oropouche virus tropism and pathogenicity

Abstract Background Oropouche virus is an emerging arbovirus increasingly associated with neurological complications, but its human cellular tropism and potential routes to the central nervous system remain poorly defined. This study aimed to characterize infection across clinically relevant human cell types and to investigate interactions with a human blood–brain barrier model and human neuronal/glial cells. Methods A panel of human cell lines and primary human cells relevant to systemic and neurological disease was infected with Oropouche virus. Viral replication and production of infectious particles were quantified using molecular assays and infectivity titrations, and viral protein expression was assessed by immunoblotting and immunofluorescence. Barrier crossing was evaluated using a Transwell brain endothelial model with permeability monitoring, and infection dynamics in neuronal/glial cultures derived from human neural progenitors were quantified by imaging-based analyses. Group comparisons used non-parametric tests with Dunn–Bonferroni correction and Mann–Whitney tests; neuronal/glial cell counts were analysed using linear models with Fisher tests for interaction terms and multiplicity-adjusted post hoc comparisons. Results Oropouche virus productively infected hepatocyte-like and intestinal epithelial cells, with high viral RNA output and release of infectious progeny. Primary synoviocytes, chondrocytes and skeletal muscle cells were permissive but produced lower infectious titers. Brain endothelial cells were inoculated and virus was progressively detected in the basolateral compartment, while endothelial permeability remained unchanged, indicating barrier crossing without disruption. In neuronal/glial cultures, both neurons and astrocytes were susceptible; infection was associated with marked cytopathic changes and a preferential, accelerated decline in neuron abundance over time. Conclusions These findings demonstrate broad human cell tropism and support blood–brain barrier crossing without major loss of barrier integrity, alongside pronounced neuronal vulnerability. The described models provide a platform to dissect mechanisms of neuroinvasion and to evaluate targeted antiviral strategies.