Possible link between fear of disease and social prejudice

Evolutionary psychologists have postulated that prejudice against "out groups" may in part originate from a fear of catching disease.  Experiments have to some extent confirmed that people are more prejudiced when it is suggested that there is a risk of contagion.

http://www.psychologicalscience.org/index.php/news/releases/a-vaccination-against-social-prejudice.html

Whether there is any link between this and the "Broken Window Theory" remains to be seen - that when we see a neighbourhood, subliminally we perceive our health to be at risk, and a whole set of prejudices comes into play.