Is it rare to contract five diseases?

Simultaneously?: There's no rule that says you can only have one disease at a time. Recognizing that our bodies are composed of millions of chemical/electrical reactions occurring at all times, it is likely that at any given time, there will be some type of problem or abnormality occurring. 5 diseases in a lifetime is no problem. 5 at the same time would be unusual but could happen is a very sick pt.