As long as you wash it well afterwards you should be fine. I had some scrapes on my knuckles while changing the tank last week and they healed up just fine, so just remember to wash them when you're finished.
Not sure on any specific things you can contract, though.
During the winter my fingers and knuckles split open and I've never had a problem catching anything from my fish. As the others said, take precautions and wash your hands after cleaning fishtanks.