Subject: Is Encephalitis a virus all on it's own?

For a proect i am doing, my teacher has asked that we choose a virus. I found a 
chart with various viruses on it and it gave me the title Togavirus with two 
points:-yellow fever and -encephalitis
It described encephalitis as inflamation of the brain. I thought that was 
interseting, because one doesn't usually here of an inflamation in that area. 
On this site i found that it was very rare.
What i want to know is:
Why was this virus put under a category?
Is it not a virus, only a symptom?

Re: Is Encephalitis a virus all on it's own?