fever, severe headache, nausea, and vomiting. As the tissue covering the brain and spinal cord (the meninges) becomes infected and swollen, the patient will develop a stiff and painful neck.
The most common symptoms are confusion, agitated behaviors (such as thrashing, grasping, strking out at staff), visual hallucinations and headache pains.
Primary encephalitis is caused by direct infection by the virus, while secondary encephalitis is due to a post-infectious immune reaction to viral infection elsewhere in the body