symbiont-mediated perturbation of host cellular process symbiont-mediated induction of syncytium formation https://github.com/geneontology/go-ontology/issues/28791 Reactome:R-HSA-9733458 positive regulation of syncytium formation by virus A process in which a symbiont initiates, promotes, or enhances the formation of a syncytium, a mass of cytoplasm containing several nuclei enclosed within a single plasma membrane, by the fusion of the plasma membranes of two or more individual host cells. Syncytia are produced by viruses that are able to fuse directly at the cell surface without requiring endocytosis. VZ:5957 syncytium formation induced by viral infection GO:0060141 biological_process