Surely causation. Farmers store crops which attract rodents which attract felines. Wild cats that mind their manners do better in this environment. Eventually wild cats become the kitty cats we know today.
That wild cats infected humans so that humans would develope agriculture that would attract rodents for the cats to eat? That hypothesis doesn't seem very plausible...
Cat infects human A, who feeds cat in a fit of unprecedented affection. Human B sees another human with a cat and wants to be their friend. Repeat until cat friend puddle is too large for local flora to sustain. Human Z invents agriculture, attracting rats. I'm not sure this is terribly plausible, but I do have a cat on my lap.
