Electron microscopic study of persistent dengue virus infection: analysis using a cell line persistently infected with Dengue-2 virus.

We investigated persistent infection of Epstein-Barr virus (EBV)-transformed lymphoblastoid cells with dengue virus using a transmission electron microscope. Most of the infected cells kept an intact morphology with only a few virus particles in the cytoplasm, but without any indication of active viral replication. Some cells were apoptotic and a few dengue virus particles were present in these apoptotic cells. Raji cells acutely infected with dengue-2 virus showed degenerative morphology. There were membranous tubular structures and many virus particles around and within the infected cells. Approximately 95% of the cells were dengue viral antigen positive in the persistently infected EBV-transformed cell line. It is likely that persistent infection is maintained mainly by the division of infected cells without cytopathic effect by dengue-2 virus.