Futuristic-ish + illiterate assassin = PURE AWESOMENESS! Thus is the story I want you to concentrate on. Because I'm selfish ;-)

I say to make up a lab-create disease. Essentially, doesn't fiction = making shit up? ;-) Only I'd want you to know the unknown nature, come up with a pseudo-scientific explanation. Because it's annoying when writers don't even bother to FAKE believability ;-)