|Genome: RNA Virus, Negative ssRNA Virus||Structure: Enveloped Virus|
- Paramyxoviruses are a family of related viruses which initially infect the upper respiratory tract. More serious clinical consequences result from spread of the viruses, some of which can occur viremically (Measles and Mumps), and others which can only spread contiguously (Parainfluenza and RSV). These viruses typically infect infants and children although they can cause disease in adults. All of these viruses possess the "F Protein" envelope protein that causes fusion of adjacently-infected host cells which can appear as multi-nucleated syncytia upon microscopy.