What Causes Viral Encephalitis?

I have just returned from hospital having been diagnosed with encephalitis, high blood pressure induced. Can you please give me more information on this. My symptoms presented as: my head was extremely hot in fact boiling. Though my body was ok I feel. Unfortunately dFeeling unwell,confusion,severe headaches, vision amnesia, disturbances neck pressure,I have had a boiling head that caused a rash, my history here is in 1995 I was hospitalised and isolated having just returned this was in the UK.with what I now know was viral encephalitis. This I caught in Nigeria possibly when I was stranded on a small river and had to spend time there These same symptoms represented only much worse, had complete memory loss amenesia and took a long time to recover 2years. Having just had an MRI associated with this episode, they found I had some brain damage not recent. Definitely not this episode. I m experiencing the same symptoms now. Please help me for they are ignoring any association. I am suffering from amnesia and great short term memory failure plus confusion,I feel very vulnerable you. What would you advise me now to do. My blood pressure is up and down I am medicated, I presented with 220/90 much better now, though still a problem nothing like the episode recently presented Yours gratefully Trish Dixon