It is everywhere, unfortunately no country is immune to it. The big issue is that some countries dont recognise ME/CFS as a real illness at all and it hence "dont exist" there as such. There was someone on this forum not long ago who I chatted to in the chat who was in a country in which it isnt at all aknowledged and in his country there wasnt even any associations or support groups for it either.
Many non English speaking thou do have their own associations or support groups and some also call it something different then CFS. (CVS?? I cant quite remember but it was something different anyway).
It is quite possible to be slightly different rates of it in different countries even if the same definitions were to be used.. due to the different triggering factors which could come into things in different countries... eg lyme in some countries in which 10% dont recover and end up being diagnosed with CFS.
In Australia thou we dont have Lyme as such (thou we do have Rickettsia another tick illness which many CFSers do also carry).. we have a mosquito triggered illness called Ross River Virus esp in our Aussie tropic regions which 10% who are affected dont recover and end up with CFS diagnoses.