This reply probably comes too late, but I was able to buzz saw through Virus on normal without too much trouble.
The advantage of the virus is also its disadvantage; its mutation capability. The trick is to focus early on entirely on transmission and abilities. The virus will effectively mutate lethality on its own after a bit, so don't worry about that piece too much.
I believe I focused on water and blood as transmission vehicles (in that order) and spent most of my early points on temperature and drug resistance. Once I had spread around enough, I took genetic hardening and then quickly made myself more lethal.
Hope that helps! Remember that you can always devolve an ability, so if the virus brings attention to itself, you can devolve something that is too scary to dial back the human response.
Good luck! If it makes you guys feel any better, I'm stuck on Fungus big time.