Not very likely. Most pathogens are only able to survive outside host for only a limited amount of time. I can't give you exact numbers for Yersinia pestis, but

Not very likely. Most pathogens are only able to survive outside host for only a limited amount of time. I can't give you exact numbers for Yersinia pestis, but it's certainly not centuries. One recent example of what you suggest is the recent Anthrax outbreak in Siberia. Though in this situation we are talking 1) about a pathogen that is particularly famous for ability to form spores and survive a long time and 2) frozen state