I read enough books on viruses to qualify for some kind of horrible extra-credit program, audited a bunch of courses at UC Berkeley and at the California Academy of Sciences, and then started phoning the CDC persistently and asking them horrible questions.
The first time I called the CDC, I said that I wanted to talk to someone about possibly designing a zombie virus. “I’m a writer, blah-blah-blah.” And the lady who answered the phone was like, “Uh …”
I said, “My name’s Seanan McGuire. Can I leave a number? Can I do this?”
And she went, “Wait. Are you ‘The Black Death’ girl?”
“Yeah.”
She says, “Sing for me!”
So I sang “The Black Death” for the receptionist at the CDC, at which point she actually helped me find people to talk to.
So every time I came up with a new iteration of [the virus], I would call back and say, “If I did this, this, this, this, this and this, could I raise the dead?” And every single time they would say, “No.”
And I’d say, “OK,” hang up, and go back to working. After about the 17th time, I called and said, “If I did this, this, this, this, this, this and this, could I raise the dead?” And got, “Don’t … don’t do that.” And at that point, I knew I had a viable virus.