Mumps is a disease caused by a virus that usually spreads through saliva and can infect many parts of the body, especially the parotid salivary glands. These glands, which produce saliva for the mouth, are found toward the back of each cheek, in the area between the ear and jaw. In cases of mumps, these glands typically swell and become painful.
After a case of mumps it is very unusual to have a second bout because one attack of mumps almost always gives lifelong protection against another. However, other infections can also cause swelling in the salivary glands, which might lead a parent to mistakenly think a child has had mumps more than once.
Mumps can lead to inflammation and swelling of the brain and other organs, although this is not common. Encephalitis (inflammation of the brain) and meningitis (inflammation of the lining of the brain and spinal cord) are both rare complications of mumps. Symptoms appear in the first week after the parotid glands begin to swell and may include: high fever, stiff neck, headache, nausea and vomiting, drowsiness, convulsions, and other signs of brain involvement.