I was in Vegas end of January(actually heard about Kobe's helicopter crash there). I remember it was a blip on the radar at the time, but people were still thinking that it was localized to China. While they do keep casinos pretty clean, there is still just a lot of hand to machine contact and not to mention higher than average smoking(raising your dirty hand to your mouth). It is a pretty phenomenally low number. I wonder, though if its low because of the transient nature of people in Vegas. They could have gone to vegas and gotten sick long after returning home.