Dear of troy: to some extent the old miasma lives on in the form of aerosols. E.G. it could be shown that the pattern of distribution of a disease caused by slaughter of infected animals in Chicago was related to prevalent wind direction. The NIH had a case of Q fever, which could only be explained by very long travel down a couple long corridors on different levels. In about 1956, I think it was, NEJM published article about anaethetist who was carrier for penicillin resistant staph, causing wound infections by passing flatus in the OR. In WWII, workers building airfield in Southern California stirred up spores of crytococcus, I think it was, causing numerous cases thereof. So miasma theory wasn't all baloney. They just sliced it too thin.