I had a theory about this illness.

I dance a bit of salsa, and sometimes there were cuban DJs at the festivals I visited. They all always tended to do one thing with their sound setup: they overamplified the higher part of the audio spectrum, producing a hissing distortion of sound. It had an effect on me very similar on what is described about Havana embassy: headache and slight nausea.

I tried talking to those DJs about it, and they told me that that's the way they like it. So I think that maybe you'd sickness is explained by cubans listening to their music the way they like it.

But that was before Vienna. Maybe there was a salsa festival recently?