Color enhanced Transmission Electron Micrograph (TEM) reveals the morphologic traits of the Respiratory Syncytial Virus (RSV). Human respiratory syncytial virus (HRSV) is a syncytial virus that causes respiratory tract infections. It is a major cause of lower respiratory tract infections and hospital visits during infancy and childhood. HRSV spreads easily by direct contact, and can remain viable for a half an hour or more on hands or for up to 5 hours on countertops. Childcare facilities allow for rapid child-to-child transmission in a short period of time. HRSV is a negative-sense, single-stranded RNA virus of the family Pneumoviridae. Its name comes from the fact that F proteins on the surface of the virus cause the cell membranes on nearby cells to merge, forming syncytia. Magnification: unknown.