And fumigation should really be broken into two separate categories: fumigation for pests, and fumigation for infectious disease. They are very different, as in

And fumigation should really be broken into two separate categories: fumigation for pests, and fumigation for infectious disease. They are very different, as infectious diseases cannot be seen: in a world where no one knows about microbes and viruses, people will do peculiar things based on their theory of disease. History provides many examples of people doing odd things to prevent plagues and disease, many of which are far stranger (and less effective) than "cleanse the buildings with fire".