It often also affects the meninges (the membranous coverings of the brain and spinal cord), causing meningoencephalitis. It is the reaction of the body's immune system to infection or invasion, and is often caused by a viral infection or a reaction to a virus or foreign protein. The viruses that cause primary, or viral encephalitis can be epidemic, like Polio, or sporadic, including herpes simplex virus, type 1 (HSV-1), and mumps. It is caused by direct viral infection, whilst secondary encephalitis is caused by an immune reaction to viral infection somewhere else in the
It often also affects the meninges (the membranous coverings of the brain and spinal cord), causing meningoencephalitis. It is the reaction of the body's immune system to infection or invasion, and is often caused by a viral infection or a reaction to a virus or foreign protein. The viruses that cause primary, or viral encephalitis can be epidemic, like Polio, or sporadic, including herpes simplex virus, type 1 (HSV-1), and mumps. It is caused by direct viral infection, whilst secondary encephalitis is caused by an immune reaction to viral infection somewhere else in the