Encephalitis describes an inflammation of the brain, most commonly caused by a viral infection (eg. measles encephalitis, cytomegalic inclusion disease, rubella syndrome, congenital syphilis, herpes simplex encephalitis and toxoplasmosis).

It frequently occurs in conjunction with meningitis, and may also occur following certain vaccinations. If a viral infection occurs in a child and is not treated or improperly treated, serous brain damage can occur. Parents must ensure that their children are seen by a doctor immediately if a viral infection is suspected. It is vital that children take the full course of medicine prescribed by a doctor to treat the infection.