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). "