A quirky Joe Dator cartoon from the January 20th issue of the New Yorker:
(#1) “We’re not a seafood restaurant–this building has a pretty severe lobster infestation.”
NOAD‘s account of the everyday usage of infestation (with notes added by me in square brackets):
noun infestation: the presence of an unusually large number of insects or animals [not plants or microbes] in a place, typically so as to cause damage or disease [of concern to human beings]: infestation with head lice is widespread | efforts were made to deal with an infestation of rats in the building.