The good fortune of the welcomed. (had to antonymize it to see
  how absurd the opposite would be - not making fun of it - far
  from it - but i like playing with words). "The happiness of the
  natives'. (if you use plague like 'annoy / bother / pesty"
  rather than a rat-spread bacterial infection) and Exiled (like
  an exiled people vs the natives / local people / etc). "