Damn near anything kills more people than terrorism, really. Terrorists are not efficient at anything except making people freak out. Which is why I make a point of not freaking out about anything terrorist related. :)

The industrialized world isn't perfect, no. However, we very rarely have thousands of people dying of dysentery any more (http://www.infoplease.com/cig/dangerous-diseases-epidemics/epidemic-dysentery.html). And as I posted a while back, the rates of infection with tuberculosis plummeted when we started selling pasteurized milk instead of unpasteurized. Incidentally--you can pasteurize your own milk at home, after you milk it out of your own cow. It's not something that has to be store-bought.