Powassan virus?

I hope thing are going well today. I was just brushing up on my viral encephalitides and paraneoplastic syndromes. I came across this helpful summary article on viral encephalitis-- which it still sounds most likely to be. I found a virus that sounds like a possible cause: Powassan, an arbovirus caused by a tickbite. I'm wondering if this was tested for, or if it could be tested for??

Most of the others on this table sound relatively unlikely-- not in the right part of the world, wrong time of year, wrong symptom complex, etc. http://www.emedicine.com/neuro/topic393.htm

The more I read about the neuro paraneoplastic syndromes, the less likely it sounds. Limbic encephalitis is one of those-- 60% of people who have it have an underlying cancer. Its features do not sound consistent with what Susan has, from what I've read.