I have a little bit of that, obviously related to OCD, but I'm more the other way around - I can stand dirt for a while but I can't give blood because I fear being contaminated by a dirty needle or some other mishap.In January my therapy will focus on my mysophobia. I suspect it's related with control, since I have no problems with giving blood but I cannot stand having dirt on my hands even if for few minutes.
I wonder if mysophobia might be a good thing though. Today people live in close proximity to each other in large cities and travel more than ever. If it wasn't for the population growth and the urbanization HIV would probably have stayed more or less in Africa, maybe only part of it.