Just came across this great article in the journal Philosophical Transactions for the Royal Society B, titled "Why Disgust Matters." In the paper Valerie Curtis of the London School of Hygiene and Tropical Medicine argues that the human feeling of "disgust" evolved to motivate infectious disease avoidance. She suggests that a better understanding of disgust could be harnessed to combat the behavioural causes of infectious and chronic disease such as diarrheal disease, influenza and even smoking.
You could imagine that more knowledge around "disgust" or what motivates good behavior (covering your face when you sneeze or washing your hands) could greatly improve infection prevention in hospitals.
Curtis V, Phil. Trans. R. Soc. B 12 December 2011 vol. 366 no. 1583 3478-3490 (abstract) (full text)