It may not just be having mono, it's the way some people are genetically programmed to respond to mono. Or perhaps a more virulent strain of mono. I know there are two different kinds, one where you have a sore throat and one where you don't, and the mono w/out sore throat is much worse. I had it when I was 29 and was off work for a month, sleeping all the time, unable to even vacuum the house. I also was in a mental fog; for example, I got lost coming home from the post office and a 10 minute drive took me an hour.

I have NEVER felt the same since I had mono, and I could tell even after I recovered from the acute disease that my recovery had stalled at a point drastically below the pre-mono normal. I can remember telling a co-worker that I knew I was going to feel like crap for the rest of my life, that I was never going to get better. Boy was I right! I did improve enough to function (slowly), until after my 2nd child was born.

I am convinced that research will show a viral trigger in genetically susceptible individuals under the proper environmental conditions. Whether it will be only one virus, EBV, or several, could have something to do with the types and severity of MS.