This document summarizes information about mumps virus and disease. Mumps is an acute viral illness caused by the mumps virus, a paramyxovirus. It is transmitted through respiratory droplets and causes swelling of the salivary glands. Common symptoms include fever, headache, muscle pain and swelling of the parotid glands. Diagnosis is usually based on symptoms, though laboratory tests can provide confirmation. Prevention focuses on vaccination with the MMR vaccine.