The Collaborative International Dictionary of English v.0.48:

Infest \In*fest"\, v. t. [imp. & p. p. Infested; p. pr. & vb.
   n. Infesting.] [L. infestare, fr. infestus disturbed,
   hostile, troublesome; in in, against + the root of defendere:
   cf. F. infester. See Defend.]
   To trouble greatly by numbers or by frequency of presence; to
   disturb; to annoy; to frequent and molest or harass; as,
   fleas infest dogs and cats; a sea infested with pirates.
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         To poison vermin that infest his plants. --Cowper.
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         These, said the genius, are envy, avarice,
         superstition, love, with the like cares and passions
         that infest human life.                  --Addison.
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         And the cares, that infest the day,
         Shall fold their tents, like the Arabs,
         And as silently steal away.              --Longfellow.
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