Solanum is the name of the zombie-creating virus from the Zombie Survival Guide. It is entirely fictional, as that is a fictional book.
That's not to say that zombies are fictional, or will always be fictional. That's not to say that a virus similar to solanum couldn't be mutating
right now. And that's not to say that the Zombie Survial Guide doesn't give some pretty good tips on how to survive undead pandemic.
But as it stands, the ZSG is a work of fiction, and there are no known zombism-inducing viruses. Zombies will most likely always remain fictional.
Still, the book is a good read . As fiction.