Actually, after searching, neither smallpox nor rinderpest have had any cases for years and have been declared eradicated diseases. Although there haven't been any cases of them recently, that doesn't mean they are gone. The bacteria still exist, the only reason we haven't had cases is because of the smallpox vaccine and I haven't done enough research on rinderpest, I just know it's something to do with cattle. But still, it's because we have prevention against the diseases, the bacteria still exists. Plus, smallpox has been around for a while, most people would have built up some sort of immunity against it too. But luckily there haven't been any cases of outbreaks, although they could still happen, should someone mess up in a lab somewhere. But still, even the plague is still around, but it's so rare you wouldn't think it'd be possible to get it.