Mumps virus. Coloured Transmission Electron Micro- graph of a mumps virus Rabula inflans in cross- section. The outer coat of the virus is a layer coloured yellow/pink while the core contains RNA genetic material. The mumps virus is a member of the paramyxoviridae virus family. It causes the acute viral illness of mumps, mainly in children. Symptoms include fever, headache and vomiting, preceding swelling of the parotid salivary glands in the neck (parotitis). A complication of mumps is meningitis. It adult males, mumps may cause swelling of the testes, but it seldom leads to infertility. There are mumps vaccines. Magnification: x100,000 at 6x4.5cm size.