Mumps virus particle,coloured transmission electron micrograph (TEM). A mumps virus particle contains ribonucleic acid (RNA) enclosed in a spherical protein shell,or capsid (outer brown layer). The shell is covered in surface proteins (purple),which are used to attach to and penetrate a host cell. Once inside a cell,the virus particles (virions) use the cell machinery to make more copies of themselves. Mumps virus is a contagious paramyxovirus,causing swelling of the parotid salivary glands,fever,headache and vomiting. Infection can spread to the pancreas,brain and testicles. In adult males,infection can cause sterility. Magnification: x196,000 when printed 10 centimetres wide |