We (waytorussia.net team) went along the Trans-Siberian this August and met many many interesting people along the way.
Once we arrived on Circum Baikal road (south of Baikal -- a very picturesque railway, just on the shore of the lake), got off the train in the middle of the way to find a nice place to camp. We met a guy who was an IT specialist on this part of the rail.
He showed us a great place where we could put our tents and invited to have a couple of bootles of beer with him. :
We had a nice talk, and at one moment I asked him about encephalitis. I heard a lot about this illness, that one can get from a bite of a tick, then the person who got bitten gets inflammation of brain and either dies or becomes crazy. Of course, it happens not all the time, but there's a chance to get it, especially in Taiga forests around Novosibirsk and in some places around Baikal. The "high season" of tick activity is from May to July, but if you protect yourself with clothes, and check your body, and eliminate (very carefully) the tick who got inside your skin, then it's ok. Also you can get immunised.
Well, anyway, so I didn't get my immunisation before, cause I don't like medicines inside my body, and I asked this guy who the locals were protecting themselves against encephalitis. He told me: "Well, you know, when me and my guys we go to work, especially in May, we just drink a lot of pure spirits or vodka just before, you know, enough be drunk :wink: and then we go to work. After we arrive, even if there's a tick, I saw him, man, he sits on my skin, bites in, drinks my blood, and you know, there's so much alcohol in my blood that they just die :shock: they die and fall off... We never had problems with this kind of things here. What we are really afraid of are snakes!"
So, if you decide to go in Siberian Taiga next spring, just get some good vodka and alcohol with you and drink it every morning for immunisation purposes.
This is a local's advice, I'm not resposible for consequences...