Referring to your poll!
Unfortunately just to say viral infection is a bit limiting, as there are other infectious agents such as Mycoplasmas, which are technically mollicutes and have been implicated in the onset of this condition. So saying just 'Infection' may be more accurate.
Also there is a subset of people who get M.E./CFS/FMS following trauma - so that would have been a good one to put in there too. Some may also suggest mould exposure and toxic exposure should be options. Much more informative than 'other'.
When doing a poll one needs to look at as many relevant variables as possible, not just our particular 'pet' favourites.